question_answer 1)
If \[C+{{O}_{2}}\to C{{O}_{2}}+94.2\,kcal\] \[{{H}_{2}}+\frac{1}{2}{{O}_{2}}\to {{H}_{2}}O+68.3\,kcal\] \[C{{H}_{4}}+2{{O}_{2}}\to C{{O}_{2}}+2{{H}_{2}}O+210.8\,kcal\] then the possible heat of methane will be [MP PET 1990]
A)
47.3 kcal done
clear
B)
20.0 kcal done
clear
C)
45.9 kcal done
clear
D)
? 47.3 kcal done
clear
View Solution play_arrow
question_answer 2)
Molar heat of vaporisation of a liquid is \[6kJ\,mo{{l}^{-1}}\]. If the entropy change is \[16J\,mo{{l}^{-1}}\,{{K}^{-1}}\], the boiling point of the liquid is [KCET 2005]
A)
\[{{375}^{o}}C\] done
clear
B)
\[375K\] done
clear
C)
\[273K\] done
clear
D)
\[{{102}^{o}}C\] done
clear
View Solution play_arrow
question_answer 3)
The enthalpy of fusion of ice per mole
A)
18 kJ done
clear
B)
8 kJ done
clear
C)
80 kJ done
clear
D)
6 kJ done
clear
View Solution play_arrow
question_answer 4)
In which of the following neutralisation reactions, the heat of neutralisation will be highest [MP PMT 1989, 91; AIIMS 1999]
A)
\[N{{H}_{4}}OH\] and \[C{{H}_{3}}COOH\] done
clear
B)
\[N{{H}_{4}}OH\] and \[HCl\] done
clear
C)
\[NaOH\] and \[C{{H}_{3}}COOH\] done
clear
D)
\[NaOH\] and \[HCl\] done
clear
View Solution play_arrow
question_answer 5)
If \[S+{{O}_{2}}\to S{{O}_{2}};\,(\Delta H=-298.2)\] \[S{{O}_{2}}+\frac{1}{2}{{O}_{2}}\to S{{O}_{3}};\,(\Delta H=-98.2)\] \[S{{O}_{3}}+{{H}_{2}}O\to {{H}_{2}}S{{O}_{4}};\,(\Delta H=-130.2)\] \[{{H}_{2}}+\frac{1}{2}{{O}_{2}}\to {{H}_{2}}O;\,(\Delta H=-287.3)\] then the enthalpy of formation of \[{{H}_{2}}S{{O}_{4}}\] at 298K will be [DPMT 1983; Orissa JEE 2005]
A)
\[-433.7\,kJ\] done
clear
B)
\[-650.3\,kJ\] done
clear
C)
\[+320.5\,kJ\] done
clear
D)
\[-813.9\,kJ\] done
clear
View Solution play_arrow
question_answer 6)
From Kirchhoff's equation which factor affects the heat of reaction [MP PMT 1990]
A)
Pressure done
clear
B)
Temperature done
clear
C)
Volume done
clear
D)
Molecularity done
clear
View Solution play_arrow
question_answer 7)
The molar neutralization heat for \[KOH\] and \[HN{{O}_{3}}\] as compared to molar neutralization heat of \[NaOH\] and \[HCl\] [MP PMT 1989]
A)
Less done
clear
B)
More done
clear
C)
Equal done
clear
D)
Depends on pressure done
clear
View Solution play_arrow
question_answer 8)
An exothermic reaction is one in which the reacting substances [CPMT 1974, 79; Bihar MEE 1982; KCET 1992; JIPMER 2001]
A)
Have more energy than the products done
clear
B)
Have less energy than the products done
clear
C)
Are at a higher temperature than the product done
clear
D)
None of the above done
clear
View Solution play_arrow
question_answer 9)
The heat evolved in the combustion of benzene is given by \[{{C}_{6}}{{H}_{6}}+7\frac{1}{2}{{O}_{2}}\to 6C{{O}_{2}}(g)+3{{H}_{2}}O(l);\,\Delta H=-3264.6\,kJ\] Which of the following quantities of heat energy will be evolved when \[39\,g\,{{C}_{6}}{{H}_{6}}\] are burnt [NCERT 1978; MP PET 1990; JIPMER 2001]
A)
816.15 kJ done
clear
B)
1632.3 kJ done
clear
C)
6528.2 kJ done
clear
D)
2448.45 kJ done
clear
View Solution play_arrow
question_answer 10)
Thermochemical reactions \[C(\text{graphite})+\frac{1}{2}{{O}_{2}}(g)\to CO(g);\,\Delta H=-110.5\,kJ\] \[CO(g)+\frac{1}{2}{{O}_{2}}(g)\to C{{O}_{2}}(g);\,\Delta H=-283.2\,kJ\] From the above reaction, the heat of reaction for \[C(\text{graphite})+{{O}_{2}}(g)\to C{{O}_{2}}(g)\] will be [CPMT 1988; MP PMT 1989]
A)
? 393.7 kJ done
clear
B)
+ 393.7 kJ done
clear
C)
? 172.7 kJ done
clear
D)
+ 172.7 kJ done
clear
View Solution play_arrow
question_answer 11)
The following is (are) endothermic reaction [IIT JEE 1999]
A)
Combustion of methane done
clear
B)
Decomposition of water done
clear
C)
Dehydrogenation of ethane to ethylene done
clear
D)
Conversion of graphite to diamond done
clear
View Solution play_arrow
question_answer 12)
Evaporation of water is [CPMT 1973; DPMT 1982; MP PMT 1989; MP PET 1999]
A)
An endothermic change done
clear
B)
An exothermic change done
clear
C)
A process where no heat change occurs done
clear
D)
A process accompanied by chemical reaction done
clear
View Solution play_arrow
question_answer 13)
An exothermic reaction is one which [NCERT 1977; MP PMT 1990]
A)
Takes place only on heating done
clear
B)
Is accompanied by a flame done
clear
C)
Is accompanied by a absorption of heat done
clear
D)
Is accompanied by evolution of heat done
clear
View Solution play_arrow
question_answer 14)
An endothermic reaction is one in which [MNR 1980; NCERT 1976]
A)
Heat is converted into electricity done
clear
B)
Heat is absorbed done
clear
C)
Heat is evolved done
clear
D)
Heat is converted into mechanical work done
clear
View Solution play_arrow
question_answer 15)
Which of the following statement is correct [NCERT 1978]
A)
\[\Delta H\] is positive for exothermic reaction done
clear
B)
\[\Delta H\] is negative for endothermic reaction done
clear
C)
The heat of neutralization of strong acid and strong base is always the same done
clear
D)
The enthalpy of fusion is negative done
clear
View Solution play_arrow
question_answer 16)
The absolute enthalphy of neutralisation of the reaction \[MgO(s)+2HCl(aq)\to MgC{{l}_{2}}(aq)+{{H}_{2}}O(l)\]will be [CBSE PMT 2005]
A)
Less than \[-57.33\ kJ\ mo{{l}^{-1}}\] done
clear
B)
\[-57.33\ kJ\ mo{{l}^{-1}}\] done
clear
C)
Greater than \[-57.33\ kJ\ mo{{l}^{-1}}\] done
clear
D)
\[57.33\ kJ\ mo{{l}^{-1}}\] done
clear
View Solution play_arrow
question_answer 17)
\[\Delta H{{{}^\circ }_{f}}\] (298K) of methanol is given by the chemical equation [AIIMS 2005]
A)
\[C{{H}_{4}}(g)+1/2{{O}_{2}}(g)\to C{{H}_{3}}OH(g)\] done
clear
B)
C (graphite) \[+1/2{{O}_{2}}(g)+2{{H}_{2}}(g)\to C{{H}_{3}}OH(l)\] done
clear
C)
C (diamond) \[+1/2{{O}_{2}}(g)+2{{H}_{2}}(g)\to C{{H}_{3}}OH(l)\] done
clear
D)
\[CO(g)+2{{H}_{2}}(g)\to C{{H}_{3}}OH(l)\] done
clear
View Solution play_arrow
question_answer 18)
If \[\Delta H_{f}^{o}\] for \[{{H}_{2}}{{O}_{2}}\] and \[{{H}_{2}}O\] are \[-188\,kJ/mole\] and \[-286\,kJ/mole\]. What will be the enthalpy change of the reaction \[2{{H}_{2}}{{O}_{2}}(l)\to 2{{H}_{2}}O(l)+{{O}_{2}}(g)\] [MP PMT 1992]
A)
\[-196\,kJ/mole\] done
clear
B)
\[146\,kJ/mole\] done
clear
C)
\[-494\,kJ/mole\] done
clear
D)
\[-98\,kJ/mole\] done
clear
View Solution play_arrow
question_answer 19)
The heat of transition \[(\Delta {{H}_{t}})\] of graphite into diamond would be, where \[C(\text{graphite})+{{O}_{2}}(g)\to C{{O}_{2}}(g);\,\,\Delta H=x\,kJ\] \[C(\text{diamond})\,+{{C}_{2}}(g)\to C{{O}_{2}}(g);\,\,\Delta H=y\,kJ\] [Pb. PET 1985]
A)
\[(x+y)\,kJ\,mo{{l}^{-1}}\] done
clear
B)
\[(x-y)\,kJ\,mo{{l}^{-1}}\] done
clear
C)
\[(y-x)\,kJ\,mo{{l}^{-1}}\] done
clear
D)
None of these done
clear
View Solution play_arrow
question_answer 20)
Correct relationship between heat of fusion \[(\Delta {{H}_{fus}})\], heat of vaporization \[(\Delta {{H}_{vap}})\] and heat of sublimation \[(\Delta {{H}_{sub}})\] is
A)
\[\Delta {{H}_{fus}}=\Delta {{H}_{vap}}+\Delta {{H}_{sub}}\] done
clear
B)
\[\Delta {{H}_{vap}}=\Delta {{H}_{fus}}+\Delta {{H}_{sub}}\] done
clear
C)
\[\Delta {{H}_{sub}}=\Delta {{H}_{vap}}+\Delta {{H}_{fus}}\] done
clear
D)
\[\Delta {{H}_{sub}}=\Delta {{H}_{vap}}-\Delta {{H}_{fus}}\] done
clear
View Solution play_arrow
question_answer 21)
Which of the following is an example of endothermic reaction [MP PMT 1980]
A)
\[{{C}_{2}}{{H}_{2}}+2{{H}_{2}}\to {{C}_{2}}{{H}_{6}};\,\,\Delta E=-314.0\,kJ\] done
clear
B)
\[C+{{O}_{2}}\to C{{O}_{2}};\,\,\Delta E=-393.5\,kJ\] done
clear
C)
\[{{N}_{2}}+{{O}_{2}}\to 2NO;\,\,\Delta E-180.5\,kJ\] done
clear
D)
\[2{{H}_{2}}+{{O}_{2}}\to 2{{H}_{2}}O;\,\,\Delta E+571.8\,kJ\] done
clear
View Solution play_arrow
question_answer 22)
If the enthalpy of B is greater than of A, the reaction \[A\to B\] is [MP PMT 1997]
A)
Endothermic done
clear
B)
Exothermic done
clear
C)
Instantaneous done
clear
D)
Spontaneous done
clear
View Solution play_arrow
question_answer 23)
Given that \[2C(s)+2{{O}_{2}}(g)\to 2C{{O}_{2}}(g);\,\,\Delta H=-787\,kJ\] \[{{H}_{2}}(g)+\frac{1}{2}{{O}_{2}}(g)\to {{H}_{2}}O(l);\,\,\Delta H=-286\,kJ\] \[{{C}_{2}}{{H}_{2}}(g)+2\frac{1}{2}{{O}_{2}}(g)\to 2C{{O}_{2}}(g)+{{H}_{2}}O(l);\,\Delta H=-1301\,kJ\] Heat of formation of acetylene is [KCET 1989; Orissa JEE 2005]
A)
\[-\,1802\,kJ\] done
clear
B)
\[+\,1802\,kJ\] done
clear
C)
\[-800\,kJ\] done
clear
D)
\[+228\,kJ\] done
clear
View Solution play_arrow
question_answer 24)
Enthalpy change for reaction, \[\frac{1}{2}{{H}_{2}}+\frac{1}{2}C{{l}_{2}}\to HCl\], is called
A)
Enthalpy of combination done
clear
B)
Enthalpy of reaction done
clear
C)
Enthalpy of formation done
clear
D)
Enthalpy of fusion done
clear
View Solution play_arrow
question_answer 25)
The enthalpy of neutralization is about 57.3 kJ for the pair
A)
\[HCl\] and \[N{{H}_{4}}OH\] done
clear
B)
\[N{{H}_{4}}OH\] and \[HN{{O}_{3}}\] done
clear
C)
\[HCl\] and \[NaOH\] done
clear
D)
\[C{{H}_{3}}COOH\] and \[NaOH\] done
clear
View Solution play_arrow
question_answer 26)
Conversion of oxygen to ozone represented by the equation \[3{{O}_{2}}\to 2{{O}_{3}}\] is an endothermic reaction. Enthalpy change \[\Delta H\] accompanying the reaction [KCET 1988, 92]
A)
Is negative done
clear
B)
Is positive done
clear
C)
Is zero done
clear
D)
Depends on temperature done
clear
View Solution play_arrow
question_answer 27)
The mutual heat of neutralisation of 40 gm of \[NaOH\] and 60 gm \[C{{H}_{3}}COOH\] will be [MP PET/PMT 1988]
A)
56.1 kcal done
clear
B)
Less than 56.1 kcal done
clear
C)
More than 56.1 kcal done
clear
D)
13.7 kcal done
clear
View Solution play_arrow
question_answer 28)
The heat of formations of \[CO(g)\] and \[C{{O}_{2}}(g)\] are \[-26.4\] kcal and \[-94.0\] kcal respectively. The heat of combustion of carbon monoxide will be [MP PET/PMT 1988; EAMCET 1993]
A)
\[+26.4\,kcal\] done
clear
B)
\[-67.6\,kcal\] done
clear
C)
\[-120.6\,kcal\] done
clear
D)
\[+52.8\,kcal\] done
clear
View Solution play_arrow
question_answer 29)
The enthalpy of combustion at 25°C of H2, cyclohexane (C6H12) and cyclohexene (C6H10) are ?241, ?3920 and ?800 KJ / mole respectively. The heat of hydrogenation of cyclohexene is [BHU 2005]
A)
? 121 KJ / mole done
clear
B)
+ 121 KJ / mole done
clear
C)
? 242 KJ / mole done
clear
D)
+ 242 KJ / mole done
clear
View Solution play_arrow
question_answer 30)
Heat of neutralisation of \[N{{H}_{4}}OH\] and \[HCl\] is [EAMCET 1980; Roorkee 1990; MP PMT 1994]
A)
\[13.7\,kcal\] done
clear
B)
\[>\,13.7\,kcal\] done
clear
C)
\[<\,13.7\,kcal\] done
clear
D)
None of the above done
clear
View Solution play_arrow
question_answer 31)
Heat of combustion \[\Delta H\] of \[C{{H}_{4}},\,{{C}_{2}}{{H}_{6}},\,{{C}_{2}}{{H}_{4}}\] and \[{{C}_{2}}{{H}_{2}}\] gases are ? 212.8, ? 373.0, ? 337.0 and ? 310.5 kcal respectively at the same temperature. The best fuel among these gases is
A)
\[C{{H}_{4}}\] done
clear
B)
\[{{C}_{2}}{{H}_{6}}\] done
clear
C)
\[{{C}_{2}}{{H}_{4}}\] done
clear
D)
\[{{C}_{2}}{{H}_{2}}\] done
clear
View Solution play_arrow
question_answer 32)
Heat of formation of \[C{{O}_{2}}(g),\,\,{{H}_{2}}O(l)\] and \[C{{H}_{4}}(g)\] are ? 94.0, ? 68.4 and ? 17.9 kcal respectively. The heat of combustion of methane is
A)
? 212.9 kcal done
clear
B)
? 136.8 kcal done
clear
C)
? 304.3 kcal done
clear
D)
? 105.2 kcal done
clear
View Solution play_arrow
question_answer 33)
The heat of reaction does not depend upon
A)
Temperature of the reaction done
clear
B)
Physical state of reactants and products done
clear
C)
Whether the reaction is carried out at constant pressure or at constant volume done
clear
D)
The method by which the final products are obtained from the reactants done
clear
View Solution play_arrow
question_answer 34)
Heat of neutralisation of a strong acid by a strong base is a constant value because [KCET 1984]
A)
Salt formed does not hydrolyse done
clear
B)
Only \[{{H}^{+}}\] and \[O{{H}^{-}}\] ions react in every case done
clear
C)
The strong base and strong acid react completely done
clear
D)
The strong base and strong acid react in aqueous solution done
clear
View Solution play_arrow
question_answer 35)
Heat of neutralisation of an acid by a base is highest when [KCET 1985]
A)
Both the acid and base are weak done
clear
B)
Both the acid and base are strong done
clear
C)
The acid is strong and the base is weak done
clear
D)
The acid is weak and the base is strong done
clear
View Solution play_arrow
question_answer 36)
The standard molar heat of formation of ethane, \[C{{O}_{2}}\] and water (l) are respectively ? 21.1, ? 94.1 and ? 68.3 kcal. The standard molar heat of combustion of ethane will be [IIT JEE 1986; DPMT 2005]
A)
? 372 kcal done
clear
B)
162 kcal done
clear
C)
?240 kcal done
clear
D)
183.5 kcal done
clear
View Solution play_arrow
question_answer 37)
Which of the following reaction is endothermic [AFMC 1988]
A)
\[CaC{{O}_{3}}\to CaO+C{{O}_{2}}\] done
clear
B)
\[Fe+S\to FeS\] done
clear
C)
\[NaOH+HCl\to NaCl+{{H}_{2}}O\] done
clear
D)
\[C{{H}_{4}}+2{{O}_{2}}\to C{{O}_{2}}+2{{H}_{2}}O\] done
clear
View Solution play_arrow
question_answer 38)
In the reaction \[C{{O}_{2}}(g)+{{H}_{2}}(g)\to CO(g)+{{H}_{2}}O(g);\,\Delta H=80\,kJ\] \[\Delta H\] is known as [CPMT 1987; KCET 1993; Bihar CEE 1995]
A)
Heat of formation done
clear
B)
Heat of combustion done
clear
C)
Heat of neutralization done
clear
D)
Heat of reaction done
clear
View Solution play_arrow
question_answer 39)
Heat of combustion of a substance [CPMT 1987, 96; AFMC 1992]
A)
Is always positive done
clear
B)
Is always negative done
clear
C)
Is equal to heat of formation done
clear
D)
Nothing can be said without reaction done
clear
View Solution play_arrow
question_answer 40)
The heat change for the reaction \[{{H}_{2}}+\frac{1}{2}{{O}_{2}}\to {{H}_{2}}O\] is called
A)
Heat of reaction done
clear
B)
Heat of formation done
clear
C)
Heat of vaporisation done
clear
D)
None of the above done
clear
View Solution play_arrow
question_answer 41)
The heat change \[\Delta H\] for the reaction \[2CO+{{O}_{2}}\to 2C{{O}_{2}};\,\Delta H=-135\,kcal\] is called
A)
Heat of formation done
clear
B)
Heat of reaction done
clear
C)
Heat of combustion done
clear
D)
Heat of solution done
clear
View Solution play_arrow
question_answer 42)
The heats of combustion of rhombic and monoclinic sulphur are respectively 70960 and 71030 calories. What will be the heat of conversion of rhombic sulphur to monoclinic [MP PMT/PET 1988]
A)
70960 calories done
clear
B)
71030 calories done
clear
C)
? 70 calories done
clear
D)
+ 70 calories done
clear
View Solution play_arrow
question_answer 43)
The heat of formation of \[{{H}_{2}}O(l)\] is ? 68.0 kcal, the heat of formation of \[{{H}_{2}}O(g)\] is likely to be
A)
? 68.0 kcal done
clear
B)
? 67.4 kcal done
clear
C)
80.0 kcal done
clear
D)
? 58.3 kcal done
clear
View Solution play_arrow
question_answer 44)
Which of the following fuels will have the highest calorific value (kJ/kg) [MP PMT 1990]
A)
Charcoal done
clear
B)
Kerosene done
clear
C)
Wood done
clear
D)
Dung done
clear
View Solution play_arrow
question_answer 45)
The heat of combustion of carbon is ?94 kcal at 1 atm pressure. The intrinsic energy of \[C{{O}_{2}}\] is
A)
\[+94\,kcal\] done
clear
B)
\[-\,94\,kcal\] done
clear
C)
\[+47\,kcal\] done
clear
D)
\[-47\,kcal\] done
clear
View Solution play_arrow
question_answer 46)
The heat of neutralisation of a strong acid and a strong alkali is \[57.0\,kJ\,mo{{l}^{-1}}\]. The heat released when \[0.5\,mole\] of \[HN{{O}_{3}}\] solution is mixed with \[0.2\,mole\] of \[KOH\] is [KCET 1991; AIIMS 2002; AMU (Engg.) 2002]
A)
\[57.0\,kJ\] done
clear
B)
\[11.4\,kJ\] done
clear
C)
\[28.5\,kJ\] done
clear
D)
\[34.9\,kJ\] done
clear
View Solution play_arrow
question_answer 47)
A solution of \[500ml\] of \[0.2\,M\,KOH\] and \[500\,ml\] of \[0.2\,M\,HCl\] is mixed and stirred; the rise in temperature is \[{{T}_{1}}\]. The experiment is repeated using \[250\,ml\] each of solution, the temperature raised is \[{{T}_{2}}\]. Which of the following is true [EAMCET 1987; MP PET 1994]
A)
\[{{T}_{1}}={{T}_{2}}\] done
clear
B)
\[{{T}_{1}}=2{{T}_{2}}\] done
clear
C)
\[{{T}_{1}}=4{{T}_{2}}\] done
clear
D)
\[{{T}_{2}}=9{{T}_{1}}\] done
clear
View Solution play_arrow
question_answer 48)
Enthalpy of a compound is equal to its [CMC Vellore 1991]
A)
Heat of combustion done
clear
B)
Heat of formation done
clear
C)
Heat of reaction done
clear
D)
Heat of solution done
clear
E)
Heat of dilution done
clear
View Solution play_arrow
question_answer 49)
Which is the best definition of ?heat of neutralization? [CMC Vellore 1991]
A)
The heat set free when one gram molecule of a base is neutralized by one gram molecule of an acid in dilute solution at a stated temperature done
clear
B)
The heat absorbed when one gram molecule of an acid is neutralized by one gram molecule of a base in dilute solution at a stated temperature done
clear
C)
The heat set free or absorbed when one gram atom of an acid is neutralized by one gram atom of a base at a stated temperature done
clear
D)
The heat set free or absorbed when a normal solution containing one gram equivalent of an acid is neutralized by a normal solution containing one gram equivalent of a base at a stated temperature done
clear
E)
The heat set free when one gram equivalent of an acid is neutralized by one gram equivalent of a base in dilute solution at a stated temperature done
clear
View Solution play_arrow
question_answer 50)
The compound with negative heat of formation are known as [DPMT 1981]
A)
Endothermic compound done
clear
B)
Exothermic compound done
clear
C)
Heat of formation compound done
clear
D)
None of the above done
clear
View Solution play_arrow
question_answer 51)
If \[{{H}^{+}}+O{{H}^{-}}\to {{H}_{2}}O+13.7\,kcal\], then the heat of neutralization for complete neutralization of one mole of \[{{H}_{2}}S{{O}_{4}}\] by base will be [MP PMT 1990]
A)
13.7 kcal done
clear
B)
27.4 kcal done
clear
C)
6.85 kcal done
clear
D)
3.425 kcal done
clear
View Solution play_arrow
question_answer 52)
The lowest value of heat of neutralization is obtained for [KCET 1988; MP PMT 1990]
A)
\[HCl+NaOH\] done
clear
B)
\[C{{H}_{3}}COOH+N{{H}_{4}}OH\] done
clear
C)
\[N{{H}_{4}}OH+HCl\] done
clear
D)
\[NaOH+C{{H}_{3}}COOH\] done
clear
View Solution play_arrow
question_answer 53)
Heat of neutralisation for the given reaction \[NaOH+HCl\to NaCl+{{H}_{2}}O\] is \[57.1\,kJ\,mo{{l}^{-1}}\]. What will be the heat released when \[0.25\,mole\] of \[NaOH\] is titrated against \[0.25\,mole\] of \[HCl\] [CPMT 1990]
A)
\[22.5\,kJ\,mo{{l}^{-1}}\] done
clear
B)
\[57.1\,kJ\,mo{{l}^{-1}}\] done
clear
C)
\[14.3\,kJ\,mo{{l}^{-1}}\] done
clear
D)
\[28.6\,kJ\,mo{{l}^{-1}}\] done
clear
View Solution play_arrow
question_answer 54)
Reaction, \[{{H}_{2}}(g)+{{I}_{2}}(g)\to 2HI(g)\] \[\Delta H=-12.40\,kcal\]. According to this, the heat of formation of HI will be [MP PET 1990]
A)
12.4 kcal done
clear
B)
? 12.4 kcal done
clear
C)
? 6.20 kcal done
clear
D)
6.20 kcal done
clear
View Solution play_arrow
question_answer 55)
All reactions with chemical dissociation are [MP PMT 1990]
A)
Reversible done
clear
B)
Reversible and endothermic done
clear
C)
Exothermic done
clear
D)
Reversible or irriversible and endothermic or exothermic done
clear
View Solution play_arrow
question_answer 56)
The heat of formation is the change in enthalpy accompanying the formation of a substance from its elements at 298 K and 1 atm pressure. Since the enthalpies of elements are taken to be zero, the heat of formation \[(\Delta H)\] of compounds [NCERT 1978; KCET 1993]
A)
Is always negative done
clear
B)
Is always positive done
clear
C)
May be negative or positive done
clear
D)
Is zero done
clear
View Solution play_arrow
question_answer 57)
The heat of combustion of \[C{{H}_{4(g)}},\,{{C}_{(\text{graphite})}}\] and \[{{H}_{2(g)}}\] are \[20\,kcal,\,-40\,kcal\] and \[-10\,kcal\] respectively. The heat of formation of methane is [EAMCET 1998]
A)
\[-4.0\,kcal\] done
clear
B)
\[+40\,kcal\] done
clear
C)
\[-80\,kcal\] done
clear
D)
\[+80\,kcal\] done
clear
View Solution play_arrow
question_answer 58)
If a chemical reaction is accompanied by the evolution of heat, it is [BHU 1979]
A)
Catalytic done
clear
B)
Photochemical done
clear
C)
Endothermic done
clear
D)
Exothermic done
clear
View Solution play_arrow
question_answer 59)
A reaction that takes place with the absorption of energy is [EAMCET 1977]
A)
Burning of a candle done
clear
B)
Rusting of iron done
clear
C)
Electrolysis of water done
clear
D)
Digestion of food done
clear
View Solution play_arrow
question_answer 60)
Which of the following is an endothermic reaction [EAMCET 1980; MP PMT 1980; IIT JEE 1989; JIPMER 2002]
A)
\[2{{H}_{2}}+{{O}_{2}}\to 2{{H}_{2}}O\] done
clear
B)
\[{{N}_{2}}+{{O}_{2}}\to 2NO\] done
clear
C)
\[2NaOH+{{H}_{2}}S{{O}_{4}}\to N{{a}_{2}}S{{O}_{4}}+2{{H}_{2}}O\] done
clear
D)
\[3{{O}_{2}}+{{C}_{2}}{{H}_{5}}OH\to 2C{{O}_{2}}+3{{H}_{2}}O\] done
clear
View Solution play_arrow
question_answer 61)
One of the phenomena which cannot be described as combustion is [EAMCET 1979]
A)
Oxidation of coal in air done
clear
B)
Burning of magnesium in nitrogen done
clear
C)
Reaction of antimony in chlorine done
clear
D)
Lighting of an electric lamp done
clear
View Solution play_arrow
question_answer 62)
Which of the following statements is correct about heat of combustion [MADT Bihar 1982]
A)
It may be exothermic in some cases and endothermic in other cases done
clear
B)
It is applicable to gaseous substances only done
clear
C)
It is always an exothermic reaction done
clear
D)
Its value does not change with temperature done
clear
View Solution play_arrow
question_answer 63)
\[{{H}_{2}}+\frac{1}{2}{{O}_{2}}\to {{H}_{2}}O;\,\Delta H=-68.39\,kcal\] \[K+{{H}_{2}}O+\]Water \[\to KOH(aq)+\frac{1}{2}{{H}_{2}};\,\Delta H=-48\,kcal\] \[KOH+\]Water \[\to KOH(aq);\,\Delta H=-14\,kcal\] The heat of formation of \[KOH\] is (in kcal) [CPMT 1988]
A)
\[-68.39+48-14\] done
clear
B)
\[-68.39-48+14\] done
clear
C)
\[68.39-48+14\] done
clear
D)
68.39 + 48 + 14 done
clear
View Solution play_arrow
question_answer 64)
Which of the following reaction can be used to define the heat of formation of \[C{{O}_{2}}(g)\] [MP PMT 1989; MH CET 2001]
A)
\[C\text{(graphite)}+{{O}_{2}}(g)=C{{O}_{2}}(g)\] done
clear
B)
\[C{{H}_{4}}(g)+2{{O}_{2}}(g)=C{{O}_{2}}(g)+2{{H}_{2}}O(l)\] done
clear
C)
\[CO(g)+\frac{1}{2}{{O}_{2}}(g)=C{{O}_{2}}(g)\] done
clear
D)
\[{{C}_{6}}{{H}_{6}}(l)+7\frac{1}{2}{{O}_{2}}(g)=6C{{O}_{2}}+3{{H}_{2}}O(l)\] done
clear
View Solution play_arrow
question_answer 65)
The enthalpy of formation of ammonia is \[-46.0\,kJ\,mo{{l}^{-1}}\]. The enthalpy change for the reaction \[2N{{H}_{3}}(g)\to 2{{N}_{2}}(g)+3{{H}_{2}}(g)\] is
A)
46.0 kJ \[mo{{l}^{-1}}\] done
clear
B)
92.0 kJ \[mo{{l}^{-1}}\] done
clear
C)
? 23.0 kJ \[mo{{l}^{-1}}\] done
clear
D)
? 92.0 kJ \[mo{{l}^{-1}}\] done
clear
View Solution play_arrow
question_answer 66)
The heat of combustion of benzene determined in a bomb calorimeter is \[-870\,kcal\,mo{{l}^{-1}}\] at \[{{25}^{o}}C\]. The value of \[\Delta E\] for the reaction is
A)
\[-1740\,kcal\] done
clear
B)
\[-870\,kcal\] done
clear
C)
\[-872\,kcal\] done
clear
D)
\[-874\,kcal\] done
clear
View Solution play_arrow
question_answer 67)
The formation of water from \[{{H}_{2}}(g)\] and \[{{O}_{2}}(g)\] is an exothermic reaction because [MP PMT/PET 1988]
A)
The chemical energy of \[{{H}_{2}}(g)\] and \[{{O}_{2}}(g)\] is more than that of water done
clear
B)
The chemical energy of \[{{H}_{2}}(g)\] and \[{{O}_{2}}(g)\] is less than that of water done
clear
C)
Not dependent on energy done
clear
D)
The temperature of \[{{H}_{2}}(g)\] and \[{{O}_{2}}(g)\] is more than that of water done
clear
View Solution play_arrow
question_answer 68)
In the reaction for the transition of carbon in the diamond form to carbon in the graphite form, \[\Delta H\] is \[-453.5\,cal\]. This points out that [BHU 1981; KCET 1986, 89]
A)
Graphite is chemically different from diamond done
clear
B)
Graphite is as stable as diamond done
clear
C)
Graphite is more stable than diamond done
clear
D)
Diamond is more stable than graphite done
clear
View Solution play_arrow
question_answer 69)
In the combustion of hydrocarbons, \[\Delta H\] is [BHU 1981]
A)
Negative done
clear
B)
Zero done
clear
C)
Positive done
clear
D)
Undeterminate done
clear
View Solution play_arrow
question_answer 70)
The standard heats of formation in kcal \[mo{{l}^{-1}}\] of \[N{{O}_{2}}(g)\] and \[{{N}_{2}}{{O}_{4}}(g)\] are 8.0 and 2.0 respectively. The heat of dimerization of \[N{{O}_{2}}\] in \[kcal\] is \[2N{{O}_{2}}(g)={{N}_{2}}{{O}_{4}}(g)\] [NCERT 1983]
A)
10.0 done
clear
B)
? 6.0 done
clear
C)
? 12.0 done
clear
D)
? 14.0 done
clear
View Solution play_arrow
question_answer 71)
The difference between heats of reaction at constant pressure and at constant volume for the reaction \[2{{C}_{6}}{{H}_{6}}(l)+15{{O}_{2}}(g)\to 12C{{O}_{2}}(g)+6{{H}_{2}}O(l)\]at \[{{25}^{o}}C\]in kJ is [IIT JEE 1991; Kerala PMT 2004]
A)
?7.43 done
clear
B)
+ 3.72 done
clear
C)
?3.72 done
clear
D)
+ 7.43 done
clear
View Solution play_arrow
question_answer 72)
\[C\](diamond) \[+{{C}_{2}}(g)\to C{{O}_{2}}(g);\,\Delta H=-395\] kJ \[C\] (graphite) \[+{{O}_{2}}(g)\to C{{O}_{2}}(g);\,\Delta H=-393.5\] kJ From the data, the \[\Delta H\] when diamond is formed from graphite, is [CBSE PMT 1989; BHU 1987]
A)
\[-1.5\,kJ\] done
clear
B)
\[+\,1.5\,kJ\] done
clear
C)
\[+\,3.0\,kJ\] done
clear
D)
\[-3.0\,kJ\] done
clear
View Solution play_arrow
question_answer 73)
Which of the following values of heat of formation indicates that the product is least stable [MP PMT 1991]
A)
\[-94\,kcal\] done
clear
B)
\[-\,231.6\,kcal\] done
clear
C)
\[+21.4\,kcal\] done
clear
D)
\[+\,64.8\,kcal\] done
clear
View Solution play_arrow
question_answer 74)
Which of the following equations correctly represents the standard heat of formation \[(\Delta H_{f}^{o})\] of methane [IIT JEE (Screening) 1992]
A)
\[C(diamond)\,+2{{H}_{2}}(g)=C{{H}_{4}}(g)\] done
clear
B)
\[C(graphite)+2{{H}_{2}}(g)=C{{H}_{4}}(l)\] done
clear
C)
\[C(graphite)+2{{H}_{2}}(g)=C{{H}_{4}}(g)\] done
clear
D)
\[C(graphite)+4H=C{{H}_{4}}(g)\] done
clear
View Solution play_arrow
question_answer 75)
In which of the following reactions does the heat change represent the heat of formation of water [EAMCET 1991]
A)
\[2{{H}_{2}}(g)+{{O}_{2}}(g)\to 2{{H}_{2}}O(l);\,\Delta H=-116\,kcal\] done
clear
B)
\[{{H}_{2}}(g)+\frac{1}{2}{{O}_{2}}(g)\to {{H}_{2}}O(l);\,\Delta H=-58\,kcal\] done
clear
C)
\[{{H}^{+}}(aq.)+O{{H}^{-}}(aq.)\to 2{{H}_{2}}O(l);\,\Delta H=-13.7\,kcal\] done
clear
D)
\[{{C}_{2}}{{H}_{2}}(g)+2\frac{1}{2}{{O}_{2}}(g)\to 2C{{O}_{2}}(g)+{{H}_{2}}O(l)\]; \[\Delta H=-310\,kcal\] done
clear
View Solution play_arrow
question_answer 76)
Values of heats of formation for \[Si{{O}_{2}}\]and \[MgO\] are \[-48.4\] and \[-34.7\,kJ\] respectively. The heat of the reaction \[2Mg+Si{{O}_{2}}\to 2MgO+Si\] is [KCET 1990]
A)
\[21.16\,kJ\] done
clear
B)
\[-21.10\,kJ\] done
clear
C)
\[-13.62\,kJ\] done
clear
D)
\[13.6\,kJ\] done
clear
View Solution play_arrow
question_answer 77)
Based on the following thermochemical equations \[{{H}_{2}}O(g)+C(s)\to CO(g)+{{H}_{2}}(g);\,\Delta H=131\,kJ\] \[CO(g)+\frac{1}{2}{{O}_{2}}(g)\to C{{O}_{2}}(g);\Delta H=-282\,kJ\] \[{{H}_{2}}(g)+\frac{1}{2}{{O}_{2}}(g)\to {{H}_{2}}O(g);\,\Delta H=-242\,kJ\] \[C(s)+{{O}_{2}}(g)\to C{{O}_{2}}(g);\,\Delta H=X\,kJ\] The value of \[X\] is [CBSE PMT 1992]
A)
\[-393\,kJ\] done
clear
B)
\[-\,655\,kJ\] done
clear
C)
\[+\,393\,kJ\] done
clear
D)
\[+655\,kJ\] done
clear
View Solution play_arrow
question_answer 78)
Heat of transition is the heat evolved or absorbed when a substance is converted from [KCET 1984]
A)
Solid to liquid done
clear
B)
Solid to vapour done
clear
C)
Liquid to vapour done
clear
D)
One allotropic form to another allotropic form done
clear
View Solution play_arrow
question_answer 79)
For the allotropic change represented by equation \[C(diamond)\to C(graphite)\]; the enthalpy change is \[\Delta H=-1.89\,kJ\]. If \[6\,g\] of diamond and \[6\,g\] of graphite are separately burnt to yield carbon dioxide, the heat liberated in the first case is [KCET 1988; DPMT 2000]
A)
Less than in the second case by \[1.89\,kJ\] done
clear
B)
More than in the second case by \[1.89\,kJ\] done
clear
C)
Less than in the second case by \[11.34\,kJ\] done
clear
D)
More than in the second case by \[0.945\,kJ\] done
clear
View Solution play_arrow
question_answer 80)
For an exothermic reaction [MP PET 1994; Manipal MEE 1995]
A)
\[H\] of the products is less than \[H\] of the reactants done
clear
B)
\[H\] of the products is more than \[H\] of the reactants done
clear
C)
\[H\] of the products is equal to \[H\] of the reactants done
clear
D)
\[\Delta H\] is always positive done
clear
View Solution play_arrow
question_answer 81)
The energy evolved is highest for which of the following reactions [MP PET 1994]
A)
\[F+{{e}^{-}}\to {{F}^{-1}}\] done
clear
B)
\[Cl+{{e}^{-}}\to C{{l}^{-}}\] done
clear
C)
\[S+2{{e}^{-}}\to {{S}^{2-}}\] done
clear
D)
\[O+2{{e}^{-}}\to {{O}^{2-}}\] done
clear
View Solution play_arrow
question_answer 82)
In the combustion of \[2.0\,gm\] of methane \[25\,kcal\] heat is liberated, heat of combustion of methane would be [MP PMT 1994]
A)
\[100\,kcal\] done
clear
B)
\[200\,kcal\] done
clear
C)
\[300\,kcal\] done
clear
D)
\[400\,kcal\] done
clear
View Solution play_arrow
question_answer 83)
Complete combustion of \[C{{H}_{4}}\] gives [BHU 1995]
A)
\[C{{O}_{2}}+{{H}_{2}}O\] done
clear
B)
\[C{{O}_{2}}+{{H}_{2}}\] done
clear
C)
\[COC{{l}_{2}}\] done
clear
D)
\[CO+C{{O}_{2}}+{{H}_{2}}O\] done
clear
View Solution play_arrow
question_answer 84)
If enthalpies of formation of \[{{C}_{2}}{{H}_{4}}(g),\,C{{O}_{2}}(g)\] and \[{{H}_{2}}O(l)\] at \[{{25}^{o}}C\] and \[1\,atm\] pressure be 52, ? 394 and \[-286\,kJ\,mo{{l}^{-1}}\] respectively, the enthalpy of combustion of \[{{C}_{2}}{{H}_{4}}(g)\] will be [CBSE PMT 1995; AIIMS 1998; Pb. PMT 1999]
A)
\[+1412\,kJ\,mo{{l}^{-1}}\] done
clear
B)
\[-1412\,kJ\,mo{{l}^{-1}}\] done
clear
C)
\[+141.2\,kJ\,mo{{l}^{-1}}\] done
clear
D)
\[-141.2\,kJ\,mo{{l}^{-1}}\] done
clear
View Solution play_arrow
question_answer 85)
Carbon and carbon monoxide burn in oxygen to form carbon dioxide according to the following reactions \[C+{{O}_{2}}\to C{{O}_{2}};\,\Delta H=-394\,kJ\,mo{{l}^{-1}}\] \[2CO+{{O}_{2}}\to 2C{{O}_{2}};\,\Delta H=-569\,kJ\,mo{{l}^{-1}}\] The heat of formation of \[1\,mol\]of carbon monoxide is thus [MP PET 1995]
A)
\[-219.0\,kJ\,mo{{l}^{-1}}\] done
clear
B)
\[-109.5\,kJ\,mo{{l}^{-1}}\] done
clear
C)
\[-175.0\,kJ\,mo{{l}^{-1}}\] done
clear
D)
\[-87.5\,kJ\,mo{{l}^{-1}}\] done
clear
View Solution play_arrow
question_answer 86)
Heat of formation in the reaction \[{{H}_{2}}+C{{l}_{2}}\to 2HCl+44\,kcal\] is [MP PMT 1995]
A)
44 kcal done
clear
B)
44000 kcal done
clear
C)
22 kcal done
clear
D)
11 kcal done
clear
View Solution play_arrow
question_answer 87)
When water is added to quick lime, the reaction is [MP PMT 1995]
A)
Exothermic done
clear
B)
Endothermic done
clear
C)
Explosive done
clear
D)
None of these done
clear
View Solution play_arrow
question_answer 88)
In an exothermic reaction \[\Delta H\] is [MP PMT 1995; CPMT 1999]
A)
Positive done
clear
B)
Negative done
clear
C)
Zero done
clear
D)
Both positive or negative done
clear
View Solution play_arrow
question_answer 89)
The heat change for the following reaction \[C(s)+2S(s)\to C{{S}_{2}}(l)\] is known as [MP PMT 1996]
A)
Heat of vaporization done
clear
B)
Heat of solution done
clear
C)
Heat of fusion done
clear
D)
Heat of formation done
clear
View Solution play_arrow
question_answer 90)
The enthalpy of combustion of benzene from the following data will be (i) \[6C(s)+3{{H}_{2}}(g)\to {{C}_{6}}{{H}_{6}}(l);\,\Delta H=+45.9\,kJ\] (ii) \[{{H}_{2}}(g)+\frac{1}{2}{{O}_{2}}(g)\to {{H}_{2}}O(l);\,\Delta H=-285.9\,kJ\] (iii) \[C(s)+{{O}_{2}}(g)\to C{{O}_{2}}(g);\,\Delta H=-393.5\,kJ\]
A)
+ 3172.8 kJ done
clear
B)
? 1549.2 kJ done
clear
C)
? 3172.8 kJ done
clear
D)
? 3264.6 kJ done
clear
View Solution play_arrow
question_answer 91)
Enthalpy of formation of \[HF\] and \[HCl\] are \[-\,161\,kJ\] and \[-\,92\,kJ\] respectively. Which of the following statements is incorrect [KCET 2003]
A)
\[HCl\] is more stable than \[HF\] done
clear
B)
\[HF\] and \[HCl\] are exothermic compounds done
clear
C)
The affinity of fluorine to hydrogen is greater than the affinity of chlorine to hydrogen done
clear
D)
\[HF\] is more stable than \[HCl\] done
clear
View Solution play_arrow
question_answer 92)
The heat of reaction at constant pressure is given by [MP PMT 1997]
A)
\[{{E}_{P}}-{{E}_{R}}\] done
clear
B)
\[{{E}_{R}}-{{E}_{P}}\] done
clear
C)
\[{{H}_{P}}-{{H}_{R}}\] done
clear
D)
\[{{H}_{R}}-{{H}_{P}}\] done
clear
View Solution play_arrow
question_answer 93)
In an endothermic reaction, the value of \[\Delta H\] is [CBSE PMT 1999; AIIMS 1998; BHU 2000; MP PMT 2000]
A)
Zero done
clear
B)
Positive done
clear
C)
Negative done
clear
D)
Constant done
clear
View Solution play_arrow
question_answer 94)
\[2.2016\,gm\] of acetaldehyde produced \[13.95\,kcal\] of heat on combustion in \[{{O}_{2}}\]. Calculate the heat of combustion of \[C{{H}_{3}}CHO\] [Bihar CEE 1995]
A)
279 kcal done
clear
B)
972 kcal done
clear
C)
27.9 kcal done
clear
D)
2.79 kcal done
clear
View Solution play_arrow
question_answer 95)
\[C+\frac{1}{2}{{O}_{2}}\to CO;\,\Delta H=-42\,kJ\] \[CO+\frac{1}{2}{{O}_{2}}\to C{{O}_{2}};\,\Delta H=-24\,kJ\] The heat of formation of \[C{{O}_{2}}\] is [CPMT 1996]
A)
? 16 kJ done
clear
B)
+ 66 kJ done
clear
C)
+ 16 kJ done
clear
D)
? 66 kJ done
clear
View Solution play_arrow
question_answer 96)
Standard molar enthalpy of formation of \[C{{O}_{2}}\] is equal to [IIT JEE 1997; BHU 2001]
A)
Zero done
clear
B)
The standard molar enthalpy of combustion of gaseous carbon done
clear
C)
The sum of standard molar enthalpies of formation of \[CO\] and \[{{O}_{2}}\] done
clear
D)
The standard molar enthalpy of combustion of carbon (graphite) done
clear
View Solution play_arrow
question_answer 97)
In the complete combustion of butanol \[{{C}_{4}}{{H}_{9}}OH(l)\], if \[\Delta H\] is enthalpy of combustion and \[\Delta E\] is the heat of combustion at constant volume, then [EAMCET 1997]
A)
\[\Delta H<\Delta E\] done
clear
B)
\[\Delta H=\Delta E\] done
clear
C)
\[\Delta H>\Delta E\] done
clear
D)
\[\Delta H,\,\Delta E\] relation cannot be predicted done
clear
View Solution play_arrow
question_answer 98)
\[C+{{O}_{2}}\to C{{O}_{2}};\,\Delta H=X\] \[CO+\frac{1}{2}{{O}_{2}}\to C{{O}_{2}};\,\Delta H=Y\] Then the heat of formation of \[CO\] is [BHU 1997; DPMT 2002]
A)
\[X-Y\] done
clear
B)
\[Y-2X\] done
clear
C)
\[X+Y\] done
clear
D)
\[2X-Y\] done
clear
View Solution play_arrow
question_answer 99)
The values of heat of formation of \[S{{O}_{2}}\] and \[S{{O}_{3}}\] are \[-298.2\,kJ\] and \[-98.2\,kJ\]. The heat of reaction of the following reaction will be \[S{{O}_{2}}+\frac{1}{2}{{O}_{2}}\to S{{O}_{3}}\] [BHU 1997; CBSE PMT 2000]
A)
\[-200\,kJ\] done
clear
B)
\[-356.2\,kJ\] done
clear
C)
\[+200\,kJ\] done
clear
D)
\[-396.2\,kJ\] done
clear
View Solution play_arrow
question_answer 100)
Calculate the standard heat of formation of carbon disulphide \[(l)\], given that the standard heat of combustion of carbon \[(s)\], sulphur \[(s)\] and carbon disulphide \[(l)\] are \[-393.3,\,-293.72\] and \[-1108.76\,kJ\,mo{{l}^{-1}}\] respectively [Roorkee 1989; BHU 1997]
A)
\[-128.02\,kJ\,mo{{l}^{-1}}\] done
clear
B)
\[+12.802\,kJ\,mo{{l}^{-1}}\] done
clear
C)
\[+128.02\,kJ\,mo{{l}^{-1}}\] done
clear
D)
\[-12.802\,kJ\,mo{{l}^{-1}}\] done
clear
View Solution play_arrow
question_answer 101)
Fermentation is a reaction called [RPMT 1997]
A)
Endothermic done
clear
B)
Exothermic done
clear
C)
Is temperature done
clear
D)
Reversible done
clear
View Solution play_arrow
question_answer 102)
\[8\,gm\] of \[C{{H}_{4}}\] is completely burnt in air. The number of moles of water produced are [Orissa JEE 1997]
A)
0.5 done
clear
B)
1 done
clear
C)
2 done
clear
D)
18 done
clear
View Solution play_arrow
question_answer 103)
For the reaction \[A(g)+2B(g)\to 2C(g)+3D(g)\], the value of \[\Delta E\] at \[{{27}^{o}}C\] is 19.0 kcal. The value of \[\Delta H\] for the reaction would be \[(R=2.0\,cal\,{{K}^{-1}}mo{{l}^{-1}})\] [Roorkee Qualifying 1998]
A)
20.8 kcal done
clear
B)
19.8 kcal done
clear
C)
18.8 kcal done
clear
D)
20.2 kcal done
clear
View Solution play_arrow
question_answer 104)
The enthalpy of solution of \[BaC{{l}_{2}}(s)\] and \[BaC{{l}_{2}}.2{{H}_{2}}O(s)\] are \[-20.6\] and \[8.8\,kJ\,mo{{l}^{-1}}\] respectively. The enthalpy change for the reaction \[BaC{{l}_{2}}(s)+2{{H}_{2}}O\to \] is [Roorkee Qualifying 1998]
A)
29.4 kJ done
clear
B)
? 11.8 kJ done
clear
C)
? 20.6 kJ done
clear
D)
? 29.4 kJ done
clear
View Solution play_arrow
question_answer 105)
The enthalpy change of a reaction does not depend on [AIIMS 1997]
A)
The state of reactants and products done
clear
B)
Nature of reactants and products done
clear
C)
Different intermediate reaction done
clear
D)
Initial and final enthalpy change of a reaction done
clear
View Solution play_arrow
question_answer 106)
\[S+\frac{3}{2}{{O}_{2}}\to S{{O}_{3}}+2x\,kcal\] \[S{{O}_{2}}+\frac{1}{2}{{O}_{2}}\to S{{O}_{3}}+y\,kcal\] Find out the heat of formation of \[S{{O}_{2}}\] [AIIMS 1997; CBSE PMT 1999; KCET 1999]
A)
\[2x-y\] done
clear
B)
\[2x+y\] done
clear
C)
\[x+y\] done
clear
D)
\[2x/y\] done
clear
View Solution play_arrow
question_answer 107)
The combustion enthalpies of carbon, hydrogen and methane are \[-395.5\,kJ\,mo{{l}^{-1}}\], \[-285.8\,kJ\,mo{{l}^{-1}}\] and \[-890.4\,kJ\,mo{{l}^{-1}}\] respectively at \[{{25}^{o}}C\]. The value of standard formation enthalpies of methane at that temperature is [Pb. PMT 1998]
A)
\[890.4\,kJ\,mo{{l}^{-1}}\] done
clear
B)
\[-298.8\,kJ\,mo{{l}^{-1}}\] done
clear
C)
\[-74.7\,kJ\,mo{{l}^{-1}}\] done
clear
D)
\[-107.7\,kJ\,mo{{l}^{-1}}\] done
clear
View Solution play_arrow
question_answer 108)
Equal volumes of methanoic acid and sodium hydroxide are mixed. If \[x\] is the heat of formation of water, then heat evolved on neutralisation is [BHU 1998]
A)
More than \[x\] done
clear
B)
Equal to \[x\] done
clear
C)
Twice of \[x\] done
clear
D)
Less than \[x\] done
clear
View Solution play_arrow
question_answer 109)
The neutralisation of a strong acid by a strong base liberates an amount of energy per mole of \[{{H}^{+}}\] that [BHU 1998]
A)
Depends upon which acid and base are involved done
clear
B)
Depends upon the temperature at which the reaction takes place done
clear
C)
Depends upon which catalyst is used done
clear
D)
Is always the same done
clear
View Solution play_arrow
question_answer 110)
When \[0.5g\] of sulphur is burnt to \[S{{O}_{2}},\,4.6\,kJ\] of heat is liberated. What is the enthalpy of formation of sulphur dioxide [KCET 1998; AFMC 2001]
A)
+ 147.2 kJ done
clear
B)
? 147.2 kJ done
clear
C)
? 294.4 kJ done
clear
D)
+ 294.4 kJ done
clear
View Solution play_arrow
question_answer 111)
Ozone is prepared by passing silent electric discharge through oxygen. In this reaction [AFMC 1998]
A)
Energy is given out done
clear
B)
Energy is absorbed done
clear
C)
Oxygen is loaded with energy done
clear
D)
Oxygen is dissociated into atoms done
clear
View Solution play_arrow
question_answer 112)
Combustion of glucose takes place according to the equation, \[{{C}_{6}}{{H}_{12}}{{O}_{6}}+6{{O}_{2}}\to 6C{{O}_{2}}+6{{H}_{2}}O\],\[\Delta H=-72\,kcal\]. How much energy will be required for the production of 1.6 g of glucose (Molecular mass of glucose = 180 g) [AFMC 1999]
A)
0.064 kcal done
clear
B)
0.64 kcal done
clear
C)
6.4 kcal done
clear
D)
64 kcal done
clear
View Solution play_arrow
question_answer 113)
Given that \[C(s)+{{O}_{2}}(g)\to C{{O}_{2}}(g),\Delta H=-394kJ\] \[2{{H}_{2}}(g)+{{O}_{2}}(g)\to 2{{H}_{2}}O(l),\,\Delta H=568kJ\] \[C{{H}_{4}}(g)+2{{O}_{2}}(g)\,\,\to \,\,C{{O}_{2}}(g)+2{{H}_{2}}O(l)\]\[\Delta H=-892\,kJ\] Heat of formation of \[C{{H}_{4}}\] is [DCE 1999]
A)
? 70 kJ done
clear
B)
71.8 kJ done
clear
C)
? 244 kJ done
clear
D)
+ 782 kJ done
clear
View Solution play_arrow
question_answer 114)
Calculate the heat of formation of \[PC{{l}_{5}}(s)\] from the following data \[2P(s)+3C{{l}_{2}}(g)\,\,\to \,\,2PC{{l}_{3}}(l);\,\Delta H=-151.8\,kcal\] \[PC{{l}_{3}}(l)+C{{l}_{2}}(g)\,\,\to \,\,PC{{l}_{5}}(s);\,\,\Delta H=-32.8\,kcal\] [JIPMER 1999]
A)
? 108.7 kcal done
clear
B)
+ 108.7 kcal done
clear
C)
? 184.6 kcal done
clear
D)
+ 184.6 kcal done
clear
View Solution play_arrow
question_answer 115)
When \[50\,c{{m}^{3}}\] of a strong acid is added to \[50\,c{{m}^{3}}\] of an alkali, the temperature rises by \[{{5}^{o}}C\]. If \[250\,c{{m}^{3}}\] of each liquid are mixed, the temperature rise would be [KCET 1999]
A)
\[{{5}^{o}}C\] done
clear
B)
\[{{10}^{o}}C\] done
clear
C)
\[{{25}^{o}}C\] done
clear
D)
\[{{20}^{o}}C\] done
clear
View Solution play_arrow
question_answer 116)
\[{{H}_{2}}(g)+\frac{1}{2}{{O}_{2}}(g)\,\,\to \,\,{{H}_{2}}O(l)\]; \[\Delta H\] at 298 K = ? 285.8 kJ The molar enthalpy of vaporisation of water at 1 atm and \[{{25}^{o}}C\] is 44 kJ. The standard enthalpy of formation of 1 mole of water vapour at \[{{25}^{o}}C\] is [KCET 1999]
A)
? 241.8 kJ done
clear
B)
241.8 kJ done
clear
C)
329.8 kJ done
clear
D)
?329.8 kJ done
clear
View Solution play_arrow
question_answer 117)
When 4 g of iron is burnt to ferric oxide at constant pressure, 29.28 kJ of heat is evolved. What is the enthalpy of formation of ferric oxide (At. Wt. of Fe = 56) [AIIMS 1999]
A)
? 81.98 kJ done
clear
B)
? 819.8 kJ done
clear
C)
? 40.99 kJ done
clear
D)
+ 819.8 kJ done
clear
View Solution play_arrow
question_answer 118)
When a strong acid, strong base or their salt are dissolved in water, they are completely ionised. If a strong acid is added to a strong base, \[{{H}^{+}}\] ions from the former combine with \[O{{H}^{-}}\] ions of the latter forming water. The formation of each water molecule liberates a certain quantity of energy and the reaction is exothermic. The heat liberated when one mole of water is formed by combining hydrochloric acid and sodium hydroxide is 13.7 kcal. The heat liberated when one mole of water is formed by combining sulphuric acid and sodium hydroxide is [AMU (Engg.) 1999]
A)
25.5 kcal done
clear
B)
8.5 kcal done
clear
C)
13.7 kcal done
clear
D)
34 kcal done
clear
View Solution play_arrow
question_answer 119)
2.1 g of Fe combines with S evolving 3.77 kJ. The heat of formation of FeS in kJ/mol is [AMU (Engg.) 1999]
A)
? 1.79 done
clear
B)
? 100.5 done
clear
C)
? 3.77 done
clear
D)
None of these done
clear
View Solution play_arrow
question_answer 120)
In the reaction: \[{{H}_{2}}+C{{l}_{2}}\,\to \,2HCl,\,\Delta H=194\,kJ\]. Heat of formation of \[HCl\] is [KCET 2000; AFMC 2000; CPMT 2000]
A)
+ 97 kJ done
clear
B)
+ 194 kJ done
clear
C)
? 194 kJ done
clear
D)
? 97 kJ done
clear
View Solution play_arrow
question_answer 121)
Enthalpy of neutralisation of acetic acid by \[NaOH\] is \[-50.6\,kJ/mol.\] and the heat of neutralisation of a strong acid with a strong base is ? 55.9 kJ/mol. What is the value of \[\Delta H\] for the ionisation of \[C{{H}_{3}}COOH\] [AIIMS 2000]
A)
+ 5.3 kJ/mol done
clear
B)
+ 6.2 kJ/mol done
clear
C)
+ 8.2 kJ/mol done
clear
D)
+ 9.3 kJ/mol done
clear
View Solution play_arrow
question_answer 122)
Heat of neutralization of the acid-base reaction is 57.32 kJ for [JIPMER 2000]
A)
\[HN{{O}_{3}}+LiOH\] done
clear
B)
\[HCOOH+KOH\] done
clear
C)
\[HCl+N{{H}_{4}}OH\] done
clear
D)
\[C{{H}_{3}}COOH+NaOH\] done
clear
View Solution play_arrow
question_answer 123)
The heat change for the following reaction at \[{{298}^{o}}K\] and at constant pressure is \[+7.3\,kcal\] \[{{A}_{2}}B(s)\,\to \,2A(s)+1/2\,{{B}_{2}}(g)\], \[\Delta H=+7.3\,kcal\] The heat change at constant volume would be [DCE 2000]
A)
7.3 kcal done
clear
B)
More than 7.3 done
clear
C)
Zero done
clear
D)
None of these done
clear
View Solution play_arrow
question_answer 124)
The heat evolved in the combustion of benzene is given by the equation \[{{C}_{6}}{{H}_{6}}(l)+7\frac{1}{2}{{O}_{2}}(g)\,\,\to \,\,3{{H}_{2}}O(l)+6C{{O}_{2}}(g)\] \[\Delta H=781.0\,kcal\,\,mo{{l}^{-1}}\] Which of the following quantities of heat energy will be evolved when 39 g of benzene is burnt in an open container [MP PET 2000]
A)
122.25 kcal \[mo{{l}^{-1}}\] done
clear
B)
390.5 kcal \[mo{{l}^{-1}}\] done
clear
C)
1562.0 kcal \[mo{{l}^{-1}}\] done
clear
D)
586.75 kcal \[mo{{l}^{-1}}\] done
clear
View Solution play_arrow
question_answer 125)
\[{{H}_{2}}(g)+C{{l}_{2}}(g)\,\,\to \,\,2HCl(g)\,.\,\Delta H=-44kcal\] \[2Na(s)+2HCl(g)\,\,\to \,\,2NaCl(s)+{{H}_{2}}(g),\]\[\Delta H=-152\,kcal\] For the reaction \[Na(s)+\frac{1}{2}C{{l}_{2}}(g)\,\,\to \,\,NaCl(s),\,\Delta H=\] [KCET 2000]
A)
? 108 kcal done
clear
B)
? 196 kcal done
clear
C)
? 98 kcal done
clear
D)
54 kcal done
clear
View Solution play_arrow
question_answer 126)
The \[\Delta H_{f}^{o}\] for \[C{{O}_{2}}(g),\,CO(g)\] and \[{{H}_{2}}O(g)\] are ? 393.5, ?110.5 and ? 241.8kJmol?1 respectively. The standard enthalpy change (in kJ) for the reaction \[C{{O}_{2}}(g)+{{H}_{2}}(g)\to \] \[CO(g)+{{H}_{2}}O(g)\] is [IIT JEE (Screening) 2000]
A)
524.1 done
clear
B)
41.2 done
clear
C)
? 262.5 done
clear
D)
? 41.2 done
clear
View Solution play_arrow
question_answer 127)
Which of the following compounds will absorb the maximum quantity of heat when dissolved in the same amount of water ? The heats of solution of these compounds at \[{{25}^{o}}C\] in kJ/mole of each solute is given in brackets [AMU (Engg.) 2000]
A)
\[HN{{O}_{3}}(\Delta H=-33)\] done
clear
B)
\[KCl(\Delta H=+17.64)\] done
clear
C)
\[N{{H}_{4}}N{{O}_{3}}\,(\Delta H=+25.5)\] done
clear
D)
\[HCl\,(\Delta H=-74.1)\] done
clear
View Solution play_arrow
question_answer 128)
In the reaction \[C+2S\,\to \,C{{S}_{2}}+\Delta H,\,\Delta H\] is the [AMU (Engg.) 2000]
A)
Heat of combustion done
clear
B)
Heat of neutralization done
clear
C)
Heat of solution done
clear
D)
None of these done
clear
View Solution play_arrow
question_answer 129)
The heat of formation of methane \[C(s)+2{{H}_{2}}(g)\,\to \,C{{H}_{4}}(g)\] at constant pressure is 18500 cal at \[{{25}^{o}}C\]. The heat of reaction at constant volume would be [MH CET 2000]
A)
17904 cal done
clear
B)
18202 cal done
clear
C)
18798 cal done
clear
D)
19096 cal done
clear
View Solution play_arrow
question_answer 130)
The enthalpy of combustion of \[{{C}_{6}}{{H}_{6(l)}}\] is ? 3250 kJ. When 0.39 g of benzene is burnt excess of oxygen in an open vessel, the amount of heat evolved is [KCET 2000; AFMC 2000; DCE 2000]
A)
16.25 J done
clear
B)
16.25 kJ done
clear
C)
32.5 J done
clear
D)
32.5 kJ done
clear
View Solution play_arrow
question_answer 131)
\[C(s)+{{O}_{2}}(g)\,\to \,C{{O}_{2}};\,\,\,\,\Delta H=-94\,kcal\] \[CO(g)+\frac{1}{2}{{O}_{2}}(g)\,\to \,C{{O}_{2}};\,\,\,\Delta H=135.2\,kcal\] Then heat of formation of \[CO(g)\] is [DCE 2001]
A)
? 26.4 kcal done
clear
B)
41.2 kcal done
clear
C)
26.4 kcal done
clear
D)
? 229.2 kcal done
clear
View Solution play_arrow
question_answer 132)
The heat of neutralization of \[HCl\] and \[NaOH\] is [MP PET 2001]
A)
Zero done
clear
B)
? 57.3 kJ done
clear
C)
+ 57.3 kJ done
clear
D)
None of these done
clear
View Solution play_arrow
question_answer 133)
The following thermochemical reactions are given \[M+\frac{1}{2}{{O}_{2}}\,\,\to \,\,MO+351.4\,kJ\] \[X+\frac{1}{2}{{O}_{2}}\,\,\to \,\,XO+90.8\,kJ\] It follows that the heat of reaction for the following process \[M+XO\] ⇌ \[MO+X\] is given by [AMU 2001]
A)
422.2 kJ done
clear
B)
268.7 kJ done
clear
C)
? 442.2 kJ done
clear
D)
260.6 kJ done
clear
View Solution play_arrow
question_answer 134)
If the heat of combustion of carbon monoxide at constant volume and at \[{{17}^{o}}C\] is ? 283.3 kJ, then its heat of combustion at constant pressure \[(R=8.314\,J\,\text{degre}{{\text{e}}^{\text{-1}}}mo{{l}^{-1}})\] [CPMT 2001]
A)
? 284.5 kJ done
clear
B)
284.5 kJ done
clear
C)
384.5 kJ done
clear
D)
? 384.5 kJ done
clear
View Solution play_arrow
question_answer 135)
Heat of formation of \[{{H}_{2}}O\] is \[-188\,kJ/mole\] and \[{{H}_{2}}{{O}_{2}}\] is \[-286\,kJ/mole.\] The enthalpy change for the reaction \[2{{H}_{2}}{{O}_{2}}\,\to \,2{{H}_{2}}O+{{O}_{2}}\] is [BHU 2001]
A)
196 kJ done
clear
B)
? 196 kJ done
clear
C)
984 kJ done
clear
D)
? 984 kJ done
clear
View Solution play_arrow
question_answer 136)
The values of \[\Delta H\] for the combustion of ethene and ethyne are ? 341.1 and ? 310.0kcal respectively. Which of the following is a better fuel [BHU 2001]
A)
\[{{C}_{2}}{{H}_{2}}\] done
clear
B)
\[{{C}_{2}}{{H}_{4}}\] done
clear
C)
Both of these done
clear
D)
None of these done
clear
View Solution play_arrow
question_answer 137)
For exothermic reaction, the equilibrium constant [JIPMER 2001]
A)
Increases with increase of P done
clear
B)
Decreases with increase of P done
clear
C)
Increases with increase of temperature done
clear
D)
Decreases with increase of temperature done
clear
View Solution play_arrow
question_answer 138)
In order to decompose 9 g water 142.5 kJ heat is required. Hence the enthalpy of formation of water is [KCET 2001]
A)
? 142.5 kJ done
clear
B)
+ 142.5 kJ done
clear
C)
? 285 kJ done
clear
D)
+ 285 kJ done
clear
View Solution play_arrow
question_answer 139)
What is \[\Delta n\] for combustion of 1 mole of benzene, when both the reactants and the products are gas at 298 K [Pb. PMT 2001]
A)
0 done
clear
B)
3/2 done
clear
C)
? 3/2 done
clear
D)
½ done
clear
View Solution play_arrow
question_answer 140)
If \[C+{{O}_{2}}\to C{{O}_{2}}+94.2\,kcal\] \[{{H}_{2}}+\frac{1}{2}{{O}_{2}}\to \,{{H}_{2}}O+68.3\,kcal\] \[C{{H}_{4}}+2{{O}_{2}}\,\to \,C{{O}_{2}}+2{{H}_{2}}O+210.8\,kcal\] Then the possible heat of methane will be [UPSEAT 2001]
A)
47.3 kcal done
clear
B)
20.0 kcal done
clear
C)
45.9 kcal done
clear
D)
? 47.3 kcal done
clear
View Solution play_arrow
question_answer 141)
Heat of neutralization of strong acid and weak base is [UPSEAT 2001]
A)
\[57.1\,kJ\,mo{{l}^{-1}}\] done
clear
B)
\[13.7\,kJ\,mo{{l}^{-1}}\] done
clear
C)
Less than \[13.7\,kcal\,mo{{l}^{-1}}\] done
clear
D)
More than \[13.7\,kcal\,mo{{l}^{-1}}\] done
clear
View Solution play_arrow
question_answer 142)
A system is changed from state A to state B by one path and from B to A another path. If \[{{E}_{1}}\] and \[{{E}_{2}}\] are the corresponding changes in internal energy, then [Pb. PMT 2001]
A)
\[{{E}_{1}}+{{E}_{2}}=-ve\] done
clear
B)
\[{{E}_{1}}+{{E}_{2}}=+ve\] done
clear
C)
\[{{E}_{1}}+{{E}_{2}}=0\] done
clear
D)
None of these done
clear
View Solution play_arrow
question_answer 143)
The heat evolved during the combination of 24 g C and 128 g S following the change is \[C+{{S}_{2}}\to C{{S}_{2}};\,\Delta H=22.0\,kcal\] [MH CET 2001]
A)
11 kcal done
clear
B)
32 kcal done
clear
C)
44 kcal done
clear
D)
22 kcal done
clear
View Solution play_arrow
question_answer 144)
When the aqueous solution of 0.5 mole \[HN{{O}_{3}}\] is mixed with the 0.3 mole of \[O{{H}^{-}}\] solution, then what will be the liberated heat (Enthalpy of neutralization is = 57.1 kJ) [Kerala CET 2005]
A)
28.5 kJ done
clear
B)
17.1 kJ done
clear
C)
45.7 kJ done
clear
D)
1.7 kJ done
clear
E)
2.85 kJ done
clear
View Solution play_arrow
question_answer 145)
A cylinder of gas is assumed to contain 11.2 kg of butane \[({{C}_{4}}{{H}_{10}})\]. If a normal family needs 20000 kJ of energy per day. The cylinder will last: (Given that \[\Delta H\] for combustion of butane is ? 2658 kJ) [AMU (Engg.) 2002]
A)
20 days done
clear
B)
25 days done
clear
C)
26 days done
clear
D)
24 days done
clear
View Solution play_arrow
question_answer 146)
Compounds with high heat of formation are less stable because [KCET 2002]
A)
High temperature is required to synthesise them done
clear
B)
Molecules of such compounds are distorted done
clear
C)
It is difficult to synthesis them done
clear
D)
Energy rich state leads to instability done
clear
View Solution play_arrow
question_answer 147)
The heat evolved in the combustion of methane is given by the following equations: \[C{{H}_{4}}(g)+2{{O}_{2}}(g)\,\to \,C{{O}_{2}}(g)+{{H}_{2}}O(l);\]\[\Delta H=-890.3\,kJ\] How many grams of methane would be required to produce 445.15 kJ of heat of combustion [AMU 2002]
A)
4 g done
clear
B)
8 g done
clear
C)
12 g done
clear
D)
16 g done
clear
View Solution play_arrow
question_answer 148)
Heats of combustion \[(\Delta {{H}^{o}})\] for \[C(s),\,{{H}_{2}}(g)\] and \[C{{H}_{4}}(g)\] are \[-94,\,-68\] and \[-213\,kcal/mol.\] respectively. The value of \[\Delta {{H}^{o}}\] for the reaction, \[C(s)+2{{H}_{2}}(g)\,\to \,C{{H}_{4}}(g)\] is [CBSE PMT 2002]
A)
? 85 kcal done
clear
B)
? 111 kcal done
clear
C)
? 17 kcal done
clear
D)
? 170 kcal done
clear
View Solution play_arrow
question_answer 149)
If the value of \[\Delta H\] in a reaction is positive, then the reaction is called [BHU 2002]
A)
Exothermic done
clear
B)
Endothermic done
clear
C)
Polymorphic done
clear
D)
Polytropic done
clear
View Solution play_arrow
question_answer 150)
Enthalpy of neutralisation of \[N{{H}_{4}}OH\] and \[HCl\], is numerically [JIPMER 2002; Kurukshetra CEE 2002]
A)
\[57.1\,\,kJ\,mo{{l}^{-1}}\] done
clear
B)
\[<57.1\,\,kJ\,mo{{l}^{-1}}\] done
clear
C)
\[>57.1\,\,kJ\,mo{{l}^{-1}}\] done
clear
D)
Zero done
clear
View Solution play_arrow
question_answer 151)
The heat of neutralisation will be highest in [MP PMT 2002]
A)
\[N{{H}_{4}}OH\] and \[C{{H}_{3}}COOH\] done
clear
B)
\[N{{H}_{4}}OH\] and \[HCl\] done
clear
C)
\[KOH\] and \[C{{H}_{3}}COOH\] done
clear
D)
\[KOH\] and \[HCl\] done
clear
View Solution play_arrow
question_answer 152)
If a mole of \[{{H}_{2}}\] molecule is heated to high temperature the following reaction takes place [Kerala (Med.) 2002]
A)
\[{{H}_{2}}(g)+436\,kJ=H(g)+H(g)\] done
clear
B)
\[{{H}_{2}}(g)+820\,kJ=2{{H}_{2}}(g)\] done
clear
C)
\[2{{H}_{2}}(g)+436\,J=2{{H}_{2}}\] done
clear
D)
\[{{H}_{2}}+{{H}_{2}}={{H}^{+}}+{{H}^{+}}\] done
clear
View Solution play_arrow
question_answer 153)
Which of the following reactions is not exothermic [MP PET 2002]
A)
\[C(s)+{{O}_{2}}(g)\,\to \,C{{O}_{2}}(g)\] done
clear
B)
\[C(s)+2S(s)\,\to \,C{{S}_{2}}(g)\] done
clear
C)
\[C{{H}_{4}}(g)+2{{O}_{2}}(g)\,\to \,C{{O}_{2}}(g)+2{{H}_{2}}O(l)\] done
clear
D)
\[CO(g)+\frac{1}{2}{{O}_{2}}(g)\,\to \,C{{O}_{2}}(g)\] done
clear
View Solution play_arrow
question_answer 154)
On combustion, carbon forms two oxides CO and \[C{{O}_{2}}\], Heat of formation of \[C{{O}_{2}}\] gas is 94.3 kcal and that of CO is 26.0 kcal. Heat of combustion of carbon is [JIPMER 2002]
A)
26.0 kcal done
clear
B)
? 94.3 kcal done
clear
C)
68.3 kcal done
clear
D)
? 120.3 kcal done
clear
View Solution play_arrow
question_answer 155)
1 mole of conc. HCl requires X moles of dilute NaOH for neutralisation and 1 mole of concentrate \[{{H}_{2}}S{{O}_{4}}\] requires Y moles of small dilute \[NaOH\] then which of the following reaction is true [MH CET 2002]
A)
\[Y=\frac{1}{2}X\] done
clear
B)
\[X=\frac{1}{2}Y\] done
clear
C)
\[X=2Y\] done
clear
D)
None of these done
clear
View Solution play_arrow
question_answer 156)
Which of the reaction defines \[\Delta H_{f}^{o}\] [IIT -JEE (Screening) 2003]
A)
\[{{C}_{(\text{diamond})}}+{{O}_{2}}(g)\,\to \,C{{O}_{2}}(g)\] done
clear
B)
\[\frac{1}{2}{{H}_{2}}(g)+\frac{1}{2}{{F}_{2}}(g)\,\to \,HF(g)\] done
clear
C)
\[{{N}_{2}}(g)+3{{H}_{2}}(g)\,\to \,2N{{H}_{3}}(g)\] done
clear
D)
\[CO(g)+\frac{1}{2}{{O}_{2}}(g)\,\to \,C{{O}_{2}}(g)\] done
clear
View Solution play_arrow
question_answer 157)
One gram sample of \[N{{H}_{4}}N{{O}_{3}}\] is decomposed in a bomb calorimeter. The temperature of the calorimeter increases by 6.12 K the heat capacity of the system is 1.23 kJ/g/deg. What is the molar heat of decomposition for \[N{{H}_{4}}N{{O}_{3}}\] [AIIMS 2003]
A)
? 7.53 kJ/mol done
clear
B)
? 398.1 kJ/mol done
clear
C)
? 16.1 kJ/mol done
clear
D)
? 602 kJ/mol done
clear
View Solution play_arrow
question_answer 158)
For which one of the following equations is \[\Delta H_{\text{react}}^{o}\] equal to \[\Delta H_{f}^{o}\] for the product [CBSE PMT 2003]
A)
\[2CO(g)+{{O}_{2}}(g)\,\to \,2C{{O}_{2}}(g)\] done
clear
B)
\[{{N}_{2}}(g)+{{O}_{3}}(g)\,\to \,{{N}_{2}}{{O}_{3}}(g)\] done
clear
C)
\[C{{H}_{4}}(g)+2C{{l}_{2}}(g)\,\to \,C{{H}_{2}}C{{l}_{2}}(l)+2HCl(g)\] done
clear
D)
\[Xe(g)+2{{F}_{2}}(g)\,\to \,Xe{{F}_{4}}(g)\] done
clear
View Solution play_arrow
question_answer 159)
Enthalpy change for a reaction does not depend upon [AIEEE 2003]
A)
The physical states of reactants and products done
clear
B)
Use of different reactants for the same product done
clear
C)
The nature of intermediate reaction steps done
clear
D)
The differences in initial or final temperatures of involved substances done
clear
View Solution play_arrow
question_answer 160)
\[{{C}_{\text{dia}}}\] + \[{{O}_{2}}\to C{{O}_{2}};\] \[\Delta H=-395.3\,kJ/mole\] \[{{C}_{gr}}+{{O}_{2}}\to C{{O}_{2}};\,\Delta H=-393.4\,kJ/mole\] \[{{C}_{gr}}\to {{C}_{\text{dia}}};\,\Delta H=\] [BHU 2003]
A)
? 3.8 done
clear
B)
? 1.9 done
clear
C)
+ 3.8 done
clear
D)
+ 1.9 done
clear
View Solution play_arrow
question_answer 161)
What is the weight of oxygen that is required for the complete combustion of 2.8 kg of ethylene? [BVP 2003]
A)
9.6 kg done
clear
B)
96.0 kg done
clear
C)
6.4 kg done
clear
D)
2.8 kg done
clear
View Solution play_arrow
question_answer 162)
For complete neutralization of \[HCl\] with \[NaOH,\] the heat of neutralization is [MP PET 2003]
A)
\[+13.70\,kJ\,mo{{l}^{-1}}\] done
clear
B)
\[-13.70\,kJ\,mo{{l}^{-1}}\] done
clear
C)
\[-57.32\,kJ\,mo{{l}^{-1}}\] done
clear
D)
\[+57.32\,kJ\,mo{{l}^{-1}}\] done
clear
View Solution play_arrow
question_answer 163)
The heat of combustion of carbon to \[C{{O}_{2}}\] is \[-393.5\,kJ/mol\]. The heat released upon formation of 35.2 g of \[C{{O}_{2}}\] from carbon and oxygen gas is [UPSEAT 2004]
A)
\[+\,315\,kJ\] done
clear
B)
\[-\,31.5\,kJ\] done
clear
C)
\[-315\,kJ\] done
clear
D)
\[+31.5\,kJ\] done
clear
View Solution play_arrow
question_answer 164)
Which of the following equations correctly represents the standard heat of formation \[(\Delta H_{f}^{o})\] of methane [UPSEAT 2004]
A)
\[C\](diamond) \[+4{{H}_{(g)}}\to C{{H}_{4\,(g)}}\] done
clear
B)
\[C\] (diamond) \[+2{{H}_{2\,(g)}}\to C{{H}_{4\,(g)}}\] done
clear
C)
\[C\] (graphite) \[+2{{H}_{2\,(g)}}\to C{{H}_{4\,(g)}}\] done
clear
D)
\[C\] (graphite) \[+4{{H}_{(g)}}\to C{{H}_{4\,(g)\,}}\] done
clear
View Solution play_arrow
question_answer 165)
If the heat of formation of \[C{{O}_{2}}\] is\[-393\,kJ\]. The amount of heat evolved in the formation of 0.156 kg of \[C{{O}_{2}}\] is [MH CET 2004]
A)
\[-1357.9\,\,kJ\] done
clear
B)
\[-1275.9\,kJ\] done
clear
C)
\[-1572.0\,kJ\] done
clear
D)
\[-1165.5\,kJ\] done
clear
View Solution play_arrow
question_answer 166)
Which of the following pairs has heat of neutralisation equal to 13.7 Kcals [DCE 2003]
A)
\[HCl,\,N{{H}_{4}}OH\] done
clear
B)
\[HN{{O}_{3}},\,KOH\] done
clear
C)
\[NaOH,\,C{{H}_{3}}COOH\] done
clear
D)
\[{{H}_{2}}S{{O}_{4}},\,N{{H}_{4}}OH\] done
clear
View Solution play_arrow
question_answer 167)
The enthalpies of combustion of carbon and carbon monodie are ?393.5 and ?283 kJ mol?1 respectivley. The enthalpy of formation of carbon monoxide per mole is [AIEEE 2004]
A)
\[-676.5\,kJ\] done
clear
B)
\[676.5\,kJ\] done
clear
C)
\[110.5\,kJ\] done
clear
D)
\[-110.5\,kJ\] done
clear
View Solution play_arrow
question_answer 168)
The enthalpy of combustion of methane at \[{{25}^{o}}C\] is \[890\,kJ\]. The heat liberated when \[3.2\,g\] of methane is burnt in air is [KCET 2004]
A)
\[445\,kJ\] done
clear
B)
\[278\,kJ\] done
clear
C)
\[-890\,kJ\] done
clear
D)
\[178\,kJ\] done
clear
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question_answer 169)
If (i) \[C+{{O}_{2}}\to C{{O}_{2}}\], (ii) \[C+1/2{{O}_{2}}\to CO\], (iii) \[CO+1/2{{O}_{2}}\to C{{O}_{2}}\], the heats of reaction are \[Q,\,-12,\,-10\] respectively. Then \[Q=\] [Orissa JEE 2004]
A)
? 2 done
clear
B)
2 done
clear
C)
? 22 done
clear
D)
? 16 done
clear
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question_answer 170)
How much energy is released when 6 mole of octane is burnt in air ? Given \[\Delta H_{f}^{o}\] for \[C{{O}_{2}}(g),\,{{H}_{2}}O(g)\] and \[{{C}_{8}}{{H}_{18}}(l)\] respectively are ? 490,? 240 and + 160 kJ/mol [AIIMS 2004]
A)
? 6.2 kJ done
clear
B)
? 37.4 kJ done
clear
C)
? 35.5 kJ done
clear
D)
? 20.0 kJ done
clear
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question_answer 171)
Given : \[2Fe+\frac{3}{2}{{O}_{2}}\to F{{e}_{2}}{{O}_{3}},\,\Delta H=-193.4\,kJ\]; \[Mg+\frac{1}{2}{{O}_{2}}\to MgO,\,\Delta H=-140.2\,kJ\] What is the \[\Delta H\] of the reaction \[Mg+F{{e}_{2}}{{O}_{3}}\to 3MgO+2Fe\] [Orissa JEE 2005]
A)
? 1802 kJ done
clear
B)
+1802 kJ done
clear
C)
? 800 kJ done
clear
D)
+ 228 kJ done
clear
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question_answer 172)
The enthalpy change \[(\Delta H)\] for the neutralization of \[1M\,HCl\] by caustic potash in dilute solution at \[298K\] is [DPMT 2005]
A)
68 kJ done
clear
B)
65 kJ done
clear
C)
57.3 kJ done
clear
D)
50 kJ done
clear
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