# Solved papers for NEET Chemistry Thermodynamics / रासायनिक उष्मागतिकी NEET PYQ-Thermodynamics

### done NEET PYQ-Thermodynamics Total Questions - 81

• question_answer1) Identify the correct statement regarding entropy:                                                                   [AIPMT 1998]

A)
At absolute zero temperature, entropy of a perfectly crystalline substance is taken to be zero

B)
At absolute zero of temperature the entropy of a perfectly crystalline substance is +ve

C)
At absolute zero of temperature the entropy of all crystalline substance is to be zero

D)
At $0{}^\circ C,$ the entropy of a perfectly crystalline substance is taken to be zero

• question_answer2) One mole of an ideal gas at 300 K is expanded isothermally from an initial volume of 1 L to 10 L.  The $\Delta E$ for this process is                                                                               [AIPMT 1998]

A)
163.7 cal

B)
zero

C)
1381.1 cal

D)
9 L atm

• question_answer3) In an endothermic reaction, the value of $\Delta H$ is:                                                        [AIPMT 1999]

A)
zero

B)
positive

C)
negative

D)
constant

• question_answer4)  In the reaction $S(s)+\frac{3}{2}{{O}_{2}}(g)\xrightarrow{{}}S{{O}_{3}}(g)+2x\,kcal$ and $S{{O}_{2}}(g)+\frac{1}{2}{{O}_{2}}(g)\xrightarrow{{}}S{{O}_{3}}(s)+y\,kcal$ the heat of formation of $S{{O}_{2}}$ is:                                                                                                                          [AIPMT 1999]

A)
$(x+y)$

B)
$(x-y)$

C)
$(2x+y)$

D)
$(2x-y)$

• question_answer5) If $\Delta E$ is the heat of reaction for ${{C}_{2}}{{H}_{5}}OH(l)+3{{O}_{2}}(g)\xrightarrow{{}}2C{{O}_{2}}(g)+3{{H}_{2}}O(l)$ at constant volume, the $\Delta H$ (heat of reaction at constant pressure) at constant temperature is:             [AIPMT 2000]

A)
$\Delta H=\Delta E+RT$

B)
$\Delta H=\Delta E-RT$

C)
$\Delta H=\Delta E-2RT$

D)
$\Delta H=\Delta E+2RT$

• question_answer6) The entropy change in the fusion of one mole of a solid melting at ${{27}^{o}}C$ (Latent heat of fusion,$2930\text{ }J\text{ }mo{{l}^{-1}}$) is:                                                                                          [AIPMT 2000]

A)
$9.77\text{ }J\text{ }{{K}^{-1}}mo{{l}^{-1}}$

B)
$10.73\text{ }J\text{ }{{K}^{-1}}mo{{l}^{-1}}$

C)
$2930\text{ }J\text{ }{{K}^{-1}}mo{{l}^{-1}}$

D)
$108.5\text{ }J\text{ }{{K}^{-1}}mo{{l}^{-1}}$

• question_answer7)  The factor of $\Delta G$ values is important in metallurgy. The $\Delta G$ values for the following reactions at ${{800}^{o}}C$ are given as: ${{S}_{2}}(s)+2{{O}_{2}}(g)\to 2S{{O}_{2}}(g)\,;$           $\Delta G=-544\,kJ$ $2Zn(s)+{{S}_{2}}O\to \,2ZnS(s)\,;$ $\Delta G=-293kJ$ $2Zn(s)+{{O}_{2}}(g)\to 2ZnO(s);$   $\Delta G=-480\,kJ$ Then $\Delta G$ for the reaction $2ZnS(s)+3{{O}_{2}}(g)\xrightarrow{{}}2ZnO(s)+2S{{O}_{2}}(g)$ will be:                                                                                                                                     [AIPMT 2000]

A)
$\text{ }357\text{ }kJ$

B)
$-731\text{ }kJ$

C)
$-773\text{ }kJ~$

D)
$-229\text{ }kJ$

• question_answer8) Change in enthalpy for reaction $2{{H}_{2}}{{O}_{2}}(l)\xrightarrow{{}}2{{H}_{2}}O(l)+{{O}_{2}}(g)$ If heat of formation of ${{H}_{2}}{{O}_{2}}(l)$ and ${{H}_{2}}O(l)$ are $-188$ and $-286\text{ }kJ/mol$ respectively:       [AIPMT 2001]

A)
$-196\text{ }k\text{ }J/mol$

B)
$+\text{ }196\text{ }k\text{ }J/mol$

C)
$+948\text{ }k\text{ }J/mol$

D)
$-948\text{ }k\text{ }J/mol$

• question_answer9) When 1 mole gas is heated at constant volume, temperature is raised from 298 to 308K. Heat supplied to the gas is 500 J. Then which statement is correct?                                                                                               [AIPMT 2001]

A)
$q=w=500\,J,\,\Delta U=0$

B)
$q=\Delta U=500\,J,\,w=0$

C)
$q=w=500\,J,\,\Delta U=0$

D)
$\Delta U=0,\,\,q=w=-500\,J$

• question_answer10) Enthalpy of $C{{H}_{4}}+\frac{1}{2}{{O}_{2}}\to C{{H}_{3}}OH$ negative. If enthalpy of combustion of $C{{H}_{4}}$ and $C{{H}_{3}}OH$ are $x$ and $y$ respectively. Then which relation is correct?      [AIPMT 2001]

A)
$x>y$

B)
$x<y$

C)
$x=y$

D)
$xy$

• question_answer11)  $Pb{{O}_{2}}\xrightarrow{{}}PbO\,\,\Delta {{G}_{298}}<0$ $Sn{{O}_{2}}\xrightarrow{{}}SnO\,\,\Delta {{G}_{298}}>0$ Most probable oxidation state of Pb and Sn will be:                                                [AIPMT 2001]

A)
$P{{b}^{4+}},\,S{{n}^{4+}}$

B)
$P{{b}^{4+}},\,S{{n}^{2+}}$

C)
$P{{b}^{2+}},\,S{{n}^{2+}}$

D)
$P{{b}^{2+}},\,S{{n}^{4+}}$

• question_answer12) Unit of entropy is:                                                                                                                      [AIPMT 2002]

A)
$J{{K}^{-1}}\,mo{{l}^{-1}}$

B)
$J\,mo{{l}^{-1}}$

C)
${{J}^{-1}}{{K}^{-1}}\,mo{{l}^{-1}}$

D)
$JK\,mo{{l}^{-1}}$

• question_answer13) In a closed insulated container a liquid is stirred with a paddle to increase the temperature, which of the following is true?                                                                                                                                      [AIPMT 2002]

A)
$\Delta E=\Delta W\ne 0,\,q=0$

B)
$\Delta E=W=0,\,q\ne 0$

C)
$\Delta E=0,\,W=q\ne 0$

D)
$W=0,\,\Delta W=q\ne 0$

• question_answer14) 2 mole of ideal gas at $27{}^\circ C$ temperature is expanded reversibly from 2 L to 20 L. Find entropy change (R = 2 cal/mol K):                                                                                                                    [AIPMT 2002]

A)
92.1

B)
0

C)
4

D)
9.2

• question_answer15) Heat of combustion $\Delta {{H}^{o}}$ for $C(s),\,\,{{H}_{2}}(g)$ and$C{{H}_{4}}(g)$ are -94, -68 and -213 kcal/mol. Then $\Delta {{H}^{o}}$ for $C(s)+2{{H}_{2}}(g)\xrightarrow[{}]{{}}C{{H}_{4}}(g)$ is:  [AIPMT 2002]

A)
- 17 kcal

B)
- 111 kcal

C)
- 170 kcal

D)
- 85 kcal

• question_answer16) The densities of graphite and diamond at 298 K are 2.25 and $3.31\text{ }g\text{ }c{{m}^{-3}}$, respectively. If the standard free energy difference $(\Delta {{G}^{o}})$ is equal to $1895\text{ }J\text{ }mo{{l}^{-1}},$ the pressure at which graphite will be transformed into diamond at 298 K is:                                                         [AIPMT 2003]

A)
$9.92\times {{10}^{6}}\,Pa$

B)
$9.92\times {{10}^{5}}\,P$

C)
$9.92\times {{10}^{8}}\,Pa$

D)
$9.92\times {{10}^{7}}Pa$

• question_answer17) On the basis of the information available from the reaction $\frac{4}{3}Al+{{O}_{2}}\to \frac{2}{3}\,A{{l}_{2}}{{O}_{3}},\,\Delta G=-827\,kJ\,mo{{l}^{-1}}$ of ${{O}_{2}},$ the minimum emf required to carry out an electrolysis of $A{{I}_{2}}{{O}_{3}}$ is $(F=96500\text{ }C\text{ }mo{{l}^{-1}})$                                                                                             [AIPMT 2003]

A)
6.42 V

B)
8.56 V

C)
2.14 V

D)
4.28 V

• question_answer18) The molar heat capacity of water at constant pressure, C, is $75\text{ }J{{K}^{-1}}mo{{l}^{-1}}$. When 1.0 kJ of heat is supplied to 100 g of water which is free to expand, the increase in temperature of water is:                    [AIPMT 2003]

A)
4.8 K

B)
6.6 K

C)
1.2 K

D)
2.4 K

• question_answer19) What is the entropy change (in$J{{K}^{-1}}mo{{l}^{-1}}$) when one mole of ice is converted into water at $0{}^\circ C$? (The enthalpy change for the conversion of ice to liquid water is $6.0\text{ }kJ\text{ }mo{{l}^{-1}}$ at $0{}^\circ C$)                                                                                                                                    [AIPMT 2003]

A)
2.198

B)
21.98

C)
20.13

D)
2.013

• question_answer20) For which one of the following equations $\Delta H_{nreact}^{o}$ equal to $\Delta H_{f}^{o}$ for the product?                                                                                                                                       [AIPMT 2003]

A)
$Xe(g)+2{{F}_{2}}(g)\xrightarrow[{}]{{}}Xe{{F}_{4}}(g)$

B)
$2CO(g)+{{O}_{2}}(g)\xrightarrow[{}]{{}}2C{{O}_{2}}(g)$

C)
${{N}_{2}}(g)+{{O}_{3}}(g)\xrightarrow[{}]{{}}2C{{O}_{2}}(g)$

D)
$C{{H}_{4}}(g)+2C{{l}_{2}}(g)\xrightarrow[{}]{{}}C{{H}_{2}}C{{l}_{2}}(\ell )+2HCl\,(g)$

• question_answer21)  Formation of a solution from two components can be considered as:                         [AIPMT 2003] (1) pure solvent$\to$separated solvent molecules, $\Delta {{H}_{1}}$ (2) pure solute$\to$separated solute molecules, $\Delta {{H}_{2}}$ (3) separated solvent and solute molecules $\to$ solution, $\Delta {{H}_{3}}$ Solution so formed will be ideal if:

A)
$\Delta {{H}_{so\ln }}=\Delta {{H}_{1}}-\Delta {{H}_{2}}-\Delta {{H}_{3}}$

B)
$\Delta {{H}_{so\ln }}=\Delta {{H}_{3}}-\Delta {{H}_{1}}-\Delta {{H}_{2}}$

C)
$\Delta {{H}_{so\ln }}=\Delta {{H}_{1}}+\Delta {{H}_{2}}+\Delta {{H}_{3}}$

D)
$\Delta {{H}_{so\ln }}=\Delta {{H}_{1}}+\Delta {{H}_{2}}-\Delta {{H}_{3}}$

• question_answer22)  For the reaction, ${{C}_{3}}{{H}_{8}}(g)+5{{O}_{2}}(g)\xrightarrow[{}]{{}}3C{{O}_{2}}(g)+4{{H}_{2}}O\,(l)$ at constant temperature, $\Delta H-\Delta E$is                                                                   [AIPMT 2003]

A)
+ 3 RT

B)
- RT

C)
+ RT

D)
- 3 RT

• question_answer23)  If the bond energies of $H-H,\,\,Br-Br$ and$H-Br$ are 433, 192 and 364 kJ $mo{{l}^{-1}}$ respectively, then $\Delta {{H}^{0}}$ for the reaction${{H}_{2}}(g)+B{{r}_{2}}(g)\xrightarrow[{}]{{}}2HBr(g)$ is:           [AIPMT (S) 2004]

A)
$-261\text{ }kJ$

B)
$+103\text{ }kJ$

C)
$+261\text{ }kJ$

D)
$-103\text{ }kJ$

• question_answer24) Standard enthalpy and standard entropy changes for the oxidation of ammonia at 298 K are$-382.64\,KJ\,mo{{l}^{-1}}$ and $-145.6\,J{{K}^{-1}}\,mo{{l}^{-1}},$ respectively. Standard Gibbs energy change for the same reaction at 298 K is:                                                                                                                                     [AIPMT (S) 2004]

A)
$-2221.1\,\,kJ\,\,mo{{l}^{-1}}$

B)
$-339.3\,\,kJ\,\,mo{{l}^{-1}}$

C)
$-\,439.3\text{ }kJ\text{ }mo{{l}^{-1}}$

D)
$-523.2\,kJ\,mo{{l}^{-1}}$

• question_answer25) The maximum number of molecules is present in:                                                    [AIPMT (S) 2004]

A)
$15\,L$ of ${{H}_{2}}$ gas at STP

B)
$5\,L$ of ${{N}_{2}}$ gas at STP

C)
0.5 g of ${{H}_{2}}$ gas

D)
10 g of ${{O}_{2}}$

• question_answer26) Considering entropy (S) as a thermodynamic parameter, the criterion for the spontaneity of any process is:                                                                                                                                                           [AIPMT (S) 2004]

A)
$\Delta \,{{S}_{\text{system}}}+\Delta {{S}_{\text{surroundings}}}>0$

B)
$\Delta \,{{S}_{\text{system}}}-\Delta {{S}_{\text{surroundings}}}>0$

C)
$\Delta \,{{S}_{\text{system}}}>0$ only

D)
$\Delta {{S}_{\text{surroundings}}}>0$ only

• question_answer27) The work done during the expansion of a gas from a volume of $4\,d{{m}^{3}}$ to $6\,d{{m}^{3}}$ against a constant external pressure of 3 atm, is:                                                                                                [AIPMT (S) 2004]

A)
$-\,\,6\,\,J$

B)
$-\,\,608\,\,J$

C)
$+\text{ }304\text{ }J$

D)
$-\text{ }304\text{ }J$

• question_answer28) A reaction occurs spontaneously if:                                                                                 [AIPMT (S) 2005]

A)
$T\Delta S<\Delta H$ and both $\Delta H$ and $\Delta S$ are +ve

B)
$T\Delta S>\Delta H$ and both $\Delta H$ and $\Delta S$ are +ve

C)
$T\Delta S=\Delta H$ and both $\Delta H$ and $\Delta S$ are +ve

D)
$T\Delta S>\Delta H$ and  $\Delta H$ is + ve and $\Delta S$ is -ve

• question_answer29) Which of the following pairs of a chemical reaction is certain to result in a spontaneous reaction? [AIPMT (S) 2005]

A)
Exothermic and decreasing disorder

B)
Endothermic and increasing disorder

C)
Exothermic and increasing disorder

D)
Endothermic and decreasing disorder

• question_answer30) The absolute enthalpy of neutralisation of the reaction: $MgO(s)+2HCl\,(aq)\,MgC{{l}_{2}}(aq)$ $+{{H}_{2}}O\,(l)$ will be:                                                                                             [AIPMT (S) 2005]

A)
less than $-\text{ }57.33\text{ }kJ\text{ }mo{{l}^{-1}}$

B)
$-\text{ }57.33\text{ }kJ\text{ }mo{{l}^{-1}}$

C)
greater than $-\text{ }57.33\text{ }kJ\text{ }mo{{l}^{-1}}$

D)
$\text{ }57.33\text{ }kJ\text{ }mo{{l}^{-1}}$

• question_answer31)  Equilibrium constants ${{K}_{1}}$ and ${{K}_{2}}$ for the following equilibria: ${{N}_{2}}(g)+\frac{1}{2}{{O}_{2}}\,N{{O}_{2}}(g)\,$ and $2N{{O}_{2}}(g)\,2NO(g)+{{O}_{2}}(g)$ are related as:                                                                                                            [AIPMT (S) 2005]

A)
${{K}_{2}}=\frac{1}{{{K}_{1}}}$

B)
${{K}_{2}}=K_{1}^{2}$

C)
${{K}_{2}}=\frac{{{K}_{1}}}{2}$

D)
${{K}_{2}}=\frac{1}{K_{1}^{2}}$

• question_answer32) Identify the correct statement for change of Gibbs energy for a system $(\Delta {{G}_{system}})$ at constant temperature and pressure:                                                                                                                         [AIPMT (S) 2006]

A)
If $\Delta {{G}_{\text{system}}}>0,$ the process is spontaneous

B)
If $\Delta {{G}_{\text{system}}}=0,$ the system has attained equilibrium

C)
If $\Delta {{G}_{\text{system}}}=0,$ the system is still moving in a particular direction

D)
If $\Delta {{G}_{\text{system}}}<0,$ the process is not spontaneous

• question_answer33) Assume each reaction is carried out in an open container. For which reaction will $\Delta H=\Delta E$? [AIPMT (S) 2006]

A)
${{H}_{2}}(g)+B{{r}_{2}}(g)\,2HBr\,(g)$

B)
$C\,(s)+2{{H}_{2}}O\,\,(g)\,2{{H}_{2}}\,\,(g)+C{{O}_{2}}\,(g)$

C)
$PC{{l}_{5}}\,\,(g)\,\,~PC{{l}_{3}}\,\,(g)+C{{l}_{2}}\,\,(g)$

D)
$2\,CO\,\,(g)\text{ }+\text{ }{{O}_{2}}\,\,(g)\,\,2C{{O}_{2}}\,(s)$

• question_answer34) The enthalpy and entropy change for the reaction: $B{{r}_{2}}(l)+C{{l}_{2}}(g)\to 2BrCl(g)$ are $30\,\,kJ\,\,mo{{l}^{-1}}$ and $105\,\,k{{J}^{-1}}\,\,mo{{l}^{-1}}$ respectively. The temperature at which the reaction will be in equilibrium is:                                                                                                                                     [AIPMT (S) 2006]

A)
285.7 K

B)
273 K

C)
450 K

D)
300 K

• question_answer35)  For the reaction, $C{{H}_{4}}(g)+2{{O}_{2}}(g)\rightleftharpoons C{{O}_{2}}(g)+2{{H}_{2}}O(\ell )\,,$${{\Delta }_{r}}H=-170.8\,kJ\,mo{{l}^{-1}}$ Which of the following statements is not true?                                                                    [AIPMT (S) 2006]

A)
At equilibrium, the concentrations of $C{{O}_{2}}\,(g)$ and ${{H}_{2}}O\,(l)$ are not equal

B)
The equilibrium constant for the reaction is given by ${{K}_{p}}=\frac{[C{{O}_{2}}]}{[C{{H}_{4}}][{{O}_{2}}]}$

C)
Addition of $C{{H}_{4}}\left( g \right)$ or ${{O}_{2}}(g)$ at equilibrium will cause a shift to the right

D)
The reaction is exothermic

• question_answer36)  The following equilibrium constants are given:                                                                 [AIPMT (S) 2007] ${{N}_{2}}+3{{H}_{2}}\,\rightleftharpoons \,2N{{H}_{3}}\,;\,{{K}_{1}}$ ${{N}_{2}}+{{O}_{2}}\,\,\rightleftharpoons \,2NO\,;\,{{K}_{2}}$ ${{H}_{2}}+1/2\,{{O}_{2}}\,\rightleftharpoons \,{{H}_{2}}O\,;\,{{K}_{3}}$ The equilibrium constant for the oxidation of $N{{H}_{3}}$ by oxygen to give NO is:

A)
${{K}_{2}}K_{3}^{3}/{{K}_{1}}$

B)
${{K}_{2}}\,K_{3}^{2}/{{K}_{1}}$

C)
$K_{2}^{2}\,{{K}_{3}}/{{K}_{1}}$

D)
${{K}_{1}}\,{{K}_{2}}/{{K}_{3}}$

• question_answer37)  Consider the following reactions:                                                                                       [AIPMT (S) 2007] (i) ${{H}^{+}}(aq)+O{{H}^{-}}(aq)={{H}_{2}}O(l)$$\Delta H=-{{x}_{1}}\,kJ\,mo{{l}^{-1}}$ (ii) ${{H}_{2}}(g)+\frac{1}{2}{{O}_{2}}(g)={{H}_{2}}O(l)$$\Delta H=-{{x}_{2}}\,kJ\,mo{{l}^{-1}}$ (iii) $C{{O}_{2}}(g)+{{H}_{2}}(g)=CO(g)+{{H}_{2}}O(l)$$-{{x}_{3}}\,kJ\,mo{{l}^{-1}}$ (iv) $+{{x}_{4}}\,kJ\,mo{{l}^{-1}}$ Enthalpy of formation of ${{H}_{2}}O(l)$ is:

A)
$-{{x}_{2}}\,kJ\,mo{{l}^{-1}}$

B)
$+{{x}_{3}}\,kJ\,mo{{l}^{-1}}$

C)
$-{{x}_{4}}\,kJ\,mo{{l}^{-1}}$

D)
$-{{x}_{1}}\,kJ\,mo{{l}^{-1}}$

• question_answer38) Given that bond energies of $H-H$ and $Cl-Cl$  are $430\text{ }kJ\text{ }mo{{l}^{-1}}$ and $240\text{ }kJ\text{ }mo{{l}^{-1}}$ respectively and $\Delta {{H}_{f}}$ for $HCl$ is $-90\text{ }kJ\text{ }mo{{l}^{-1}}$. Bond enthalpy' of $HCl$ is:                                                                                                                   [AIPMT (S) 2007]

A)
$290\text{ }kJ\text{ }mo{{l}^{-1}}$

B)
$380\text{ }kJ\text{ }mo{{l}^{-1}}$

C)
\  $425\text{ }kJ\text{ }mo{{r}^{-1}}$

D)
$245\text{ }kJ\text{ }mo{{l}^{-1}}$

• question_answer39)  The equilibrium constant of the reaction:                                                                           [AIPMT (S) 2007] $Cu(s)+2A{{g}^{+}}(aq)~C{{u}^{2+}}(aq)+2Ag(s);$ $E{}^\circ =0.46V$ at $298\text{ }K$ is:

A)
$2.4\times {{10}^{10}}$

B)
$2.4\times {{10}^{50}}$

C)
$4.0\times {{10}^{10}}$

D)
$4.0\times {{10}^{15}}$

• question_answer40) The efficiency of a fuel cell is given by:                                                                                   [AIPMT (S) 2007]

A)
$\frac{\Delta H}{\Delta G}$

B)
$\frac{\Delta G}{\Delta S}$

C)
$\frac{\Delta G}{\Delta H}$

D)
$\frac{\Delta S}{\Delta G}$

• question_answer41)  Which of the following are not state functions?                                                                    [AIPMT (S) 2008] (I) $q+W$                     (II) q (III) W                                       (IV) H-TS

A)
(I) and (IV)

B)
(II), (III) and (IV)

C)
(I), (II) and (III)

D)
(II) and (III)

• question_answer42) For the gas phase reaction, $PC{{l}_{5}}_{(g)}PC{{l}_{3}}(g)+C{{l}_{2}}(g)$ which of the following conditions are correct? [AIPMT (S) 2008]

A)
$\Delta H=0$ and $\Delta S<0$

B)
$\Delta H>0$ and $\Delta S>0$

C)
$\Delta H>0$ and $\Delta S<0$

D)
$\Delta H>0$ and $\Delta S<0$

• question_answer43) What volume of .oxygen gas $({{O}_{2}})$ measured at ${{0}^{o}}C$ and 1 atm, is needed to bum completely $1\,L$ of propane gas $({{C}_{3}}{{H}_{8}})$ measured under the same conditions?               [AIPMT (S) 2008]

A)
7 L

B)
6 L

C)
5 L

D)
10 L

• question_answer44) Bond dissociation enthalpy of ${{H}_{2}},C{{l}_{2}}$ and $HCl$ are 434, 242 and 431 kJ $mo{{l}^{-1}}$ respectively. Enthalpy of formation of HCl is                                                                                                                     [AIPMT (S) 2008]

A)
$93\,kJ\,mo{{l}^{-1}}$

B)
$-245\,kJ\,mo{{l}^{-1}}$

C)
$-93\,kJ\,mo{{l}^{-1}}$

D)
$245\,kJ\,mo{{l}^{-1}}$

• question_answer45)  The dissociation equilibrium of a gas $A{{B}_{2}}$ can be represented as                     [AIPMT (S) 2008] $2A{{B}_{2}}(g)2AB(g)+{{B}_{2}}(g)$ The degree of dissociation is $'x'$ and is small compared to 1. The expression relating the degree of dissociation $(x)$ with equilibrium constant ${{K}_{p}}$ and total pressure p is

A)
$(2{{K}_{p}}/p)$

B)
${{(2{{K}_{p}}/p)}^{1/3}}$

C)
${{(2{{K}_{p}}/p)}^{1/2}}$

D)
$({{K}_{p}}/p)$

• question_answer46)  The values of ${{K}_{{{p}_{1}}}}$ and ${{K}_{{{p}_{2}}}}$ for the reactions  [AIPMT (S) 2008] $XY+Z$                                   ...(i) and                   $A2B$                          ..(ii) are in ratio of 9 : 1. If degree of dissociation of X and A be equal, then total pressure at equilibrium (i) and (ii) are in the ratio

A)
3 : 1

B)
1 : 9

C)
36 : 1

D)
1 : 1

• question_answer47)  The value of equilibrium constant of the reaction $HI(g)\frac{1}{2}{{H}_{2}}(g)+\frac{1}{2}{{I}_{2}}$ is 8.0. The equilibrium constant of the reaction                                                                          [AIPMT (S) 2008] ${{H}_{2}}(g)+{{I}_{2}}(g)2HI(g)$ will be

A)
$\frac{1}{16}$

B)
$\frac{1}{64}$

C)
16

D)
$\frac{1}{8}$

• question_answer48)  From the following bond energies:                                                  [AIPMT (S) 2009] $H-H$ bond energy: 431.37 kJ $mo{{l}^{-1}}$ $C=O$ bond energy: 606.10 kJ $mo{{l}^{-1}}$ $C-C$ bond energy: 336.49 kJ $mo{{l}^{-1}}$ $C-H$ bond energy: 410.50 kJ  $mo{{l}^{-1}}$ Enthalpy for the reaction, $\underset{\begin{smallmatrix} | \\ H \end{smallmatrix}}{\overset{\begin{smallmatrix} H \\ | \end{smallmatrix}}{\mathop{C}}}\,=\underset{\begin{smallmatrix} | \\ H \end{smallmatrix}}{\overset{\begin{smallmatrix} H \\ | \end{smallmatrix}}{\mathop{C}}}\,+H-\xrightarrow{{}}H-\underset{\begin{smallmatrix} | \\ H \end{smallmatrix}}{\overset{\begin{smallmatrix} H \\ | \end{smallmatrix}}{\mathop{C}}}\,-\underset{\begin{smallmatrix} | \\ H \end{smallmatrix}}{\overset{\begin{smallmatrix} H \\ | \end{smallmatrix}}{\mathop{C}}}\,-H$ will be

A)
$1523.6\,kJ\,mo{{l}^{-1}}$

B)
$-243.6\,kJ\,mo{{l}^{-1}}$

C)
$-120.0\,kJ\,mo{{l}^{-1}}$

D)
$553.0\,kJ\,mo{{l}^{-1}}$

• question_answer49) The values of $\Delta H$ and $\Delta S$ for the reaction, ${{C}_{(\text{graphits)}}}+C{{O}_{2}}(g)\xrightarrow[{}]{{}}\,2\,CO\,(g)$ are 170 kJ and $170\,J{{K}^{-1}},$ respectively. This reaction will be spontaneous at                                                          [AIPMT (S) 2009]

A)
710 K

B)
910 K

C)
1110 K

D)
510 K

• question_answer50) The energy absorbed by each molecule $({{A}_{2}})$ of a substance is $4.4\times {{10}^{-19}}\,J$ and bond energy per molecule is $4.0\times {{10}^{-19}}\,J$. The kinetic energy of the molecule per atom will be [AIPMT (S) 2009]

A)
$2.0\times {{10}^{-\,20}}\,J$

B)
$2.2\times {{10}^{-\,19}}\,J$

C)
$2.0\times {{10}^{-\,19}}\,J$

D)
$4.0\times {{10}^{-\,20}}\,J$

• question_answer51) For an endothermic reaction, energy of activation is ${{E}_{a}}$ and enthalpy of reaction is $\Delta H$ (both of these in kJ/mol). Minimum value of ${{E}_{a}}$  will be                                                               [AIPMT (S) 2010]

A)
less than $\Delta H$

B)
equal to $\Delta H$

C)
more than $\Delta H$

D)
equal to zero

• question_answer52) Standard entropies of ${{X}_{2}},{{Y}_{2}}$ and $X{{Y}_{3}}$ are 60, 40 and $50\,J\,{{K}^{-1}}\,mo{{l}^{-1}}$ respectively. For the reaction $\frac{1}{2}{{X}_{2}}+\frac{3}{2}{{Y}_{2}}X{{Y}_{3}};\Delta H=-30kJ,$ to be at equilibrium, the temperature should be                                                                                 [AIPMT (S) 2010]

A)
750 K

B)
1000 K

C)
1250 K

D)
500 K

Match List I (equations) with List II (types of process) and select the correct option.          [AIPMT (M) 2010]
 List I (Equations) List II (Type of process) A. A. ${{K}_{p}}>Q$ 1 Non-spontaneous B. $\Delta {{G}^{o}}\frac{\Delta H}{\Delta S}$ 4 Spontaneous

A)
 1 2 3 4

B)
 3 4 2 1

C)
 4 1 2 3

D)
 2 1 4 3

• question_answer54) Three moles of an ideal gas expanded spontaneously into vacuum. The work done will be        [AIPMT (M) 2010]

A)
infinite

B)
3 J

C)
9 J

D)
zero

• question_answer55) For vaporisation of water at 1 atm pressure, the values of $\Delta H$ and $\Delta S$ are $40.63\,kJ\,mo{{l}^{-1}}$ and $108.8\,J{{K}^{-1}}\,mo{{l}^{-1}}$, respectively. The temperature when Gibbs energy change $(\Delta G)$ for this transformation will be zero, is                                                                        [AIPMT (M) 2010]

A)
273.4 K

B)
393.4 K

C)
373.4 K

D)
293.4 K

• question_answer56)               The following two reactions are known                                           [AIPMT (M) 2010] $F{{e}_{2}}{{O}_{3}}(s)+3CO(g)\xrightarrow[{}]{{}}2Fe(s)+3C{{O}_{2}}(g);$$\Delta H=-26.8\,kJ$ $FeO(s)+CO(g)\xrightarrow[{}]{{}}Fe(s)+C{{O}_{2}}(g);$$\Delta H=-16.5\,kJ$ The value of $\Delta H$ for the following reaction $F{{e}_{2}}{{O}_{3}}(s)+CO(g)\xrightarrow[{}]{{}}2FeO(s)+C{{O}_{2}}(g)$

A)
$+10.3\,kJ$

B)
$-\,43.3\,kJ$

C)
$-\,10.3\,kJ$

D)
$+\,6.2\,kJ$

• question_answer57) If the enthalpy change for the transition of liquid water to steam is $30\,kJ\,mo{{l}^{-1}}$ at ${{27}^{o}}C,$ the entropy change for the process would be                                                                                [AIPMT (S) 2011]

A)
$1.0\,\,J\,mo{{l}^{-1}}\,{{K}^{-1}}$

B)
$0.1\,\,J\,mo{{l}^{-1}}\,{{K}^{-1}}$

C)
$100\,J\,mo{{l}^{-1}}\,{{K}^{-1}}$

D)
$10\,J\,mo{{l}^{-1}}\,{{K}^{-1}}$

• question_answer58)  Which of the following is correct option for   free expansion of an ideal gas under adiabatic condition? [AIPMT (S) 2011]

A)
$q\ne 0,\Delta T=0,W=0$

B)
$q=0,\Delta T=0,W=0$

C)
$q=0,\Delta T<0,W\ne 0$

D)
$q=0,\Delta T\ne 0,W=0$

• question_answer59)    Enthalpy change for the reaction, $4H(g)\xrightarrow[{}]{{}}2{{H}_{2}}(g)$ is $\text{ }869.6\text{ }kJ$ The dissociation energy of $H-H$ bond is

A)
$-869.6\,kJ$

B)
$+\,434.8\,kJ$

C)
$+\,217.4\,kJ$

D)
$-\,434.8\,kJ$

• question_answer60)  Consider the following processes $\Delta H\,(kJ/\,mol)$                                                        [AIPMT (M) 2011] $1/2A\to B$                  + 150 $3B\to 2C+D$              - 125 $E+A\to 2D$                + 350 For $B+D\to E+2C,\Delta H$ will be

A)
525 kJ/mol

B)
- 175 kJ/mol

C)
- 325 kJ/mol

D)
325 kJ/mol

• question_answer61) In which of the following reactions, standard reaction entropy changes $(\Delta {{S}^{o}})$ is positive and standard Gibb's energy change $(\Delta {{S}^{o}})$ decreases    sharply   with    increasing temperature?     [AIPMT (S) 2012]

A)
$C\,(\text{graphite})+\frac{1}{2}{{O}_{2}}(g)\xrightarrow[{}]{{}}CO(g)$

B)
$CO(g)+\frac{1}{2}{{O}_{2}}(g)\xrightarrow[{}]{{}}C{{O}_{2}}(g)$

C)
$Mg(s)+\frac{1}{2}{{O}_{2}}(g)\xrightarrow[{}]{{}}MgO(s)$

D)
$\frac{1}{2}C(\text{graphite})+\frac{1}{2}{{O}_{2}}(g)\xrightarrow[{}]{{}}\frac{1}{2}C{{O}_{2}}(g)$

• question_answer62) The enthalpy of fusion of water is kcal/mol. The molar entropy change for the melting of ice at ${{0}^{o}}C$ is                            [AIPMT (S) 2012]

A)
10.52 cal/(mol K)

B)
21.04 cal/(mol K)

C)
5.260 cal/ (mol K)

D)
0.526 cal/(mol K)

• question_answer63) Standard enthalpy of vaporization ${{\Delta }_{vap}}{{H}^{\Theta }}$ for water at ${{100}^{o}}C$ is $40.66\,kJ\,mo{{l}^{-1}}$. The internal energy of vaporisation .of water at ${{100}^{o}}C$ (in kJ $mo{{l}^{-1}}$ is (Assume water vapour to behave like an ideal gas). [AIPMT (S) 2012]

A)
+ 37.56

B)
- 43.76

C)
+ 43.76

D)
+ 40.66

• question_answer64) Equal volumes of two monoatomic gases, A and B, at same temperature and pressure are mixed. The ratio of specific heats $(cp/cv)$ of the mixture will be                                                                [AIPMT (M) 2012]

A)
0.83

B)
1.50

C)
3.3

D)
1.67

• question_answer65)  The Gibbs energy for the decomposition of$A{{l}_{2}}{{O}_{3}}$ at ${{500}^{o}}C$ is as follows $\frac{2}{3}A{{l}_{2}}{{O}_{3}}\xrightarrow[{}]{{}}\frac{4}{3}Al+{{O}_{2}};$ ${{\Delta }_{r}}G=+\,960\,kJ\,mo{{l}^{-1}}$ The potential difference needed for the electrolytic reduction of aluminium oxide $(A{{l}_{2}}{{O}_{3}})$ at ${{500}^{o}}C$ is at least             [AIPMT (M) 2012]

A)
4.5 V

B)
3.0 V

C)
2.5 V

D)
5.0 V

• question_answer66)  Using   the   Gibbs   energy   change                                                                                  [AIPMT 2014] $\Delta {{G}^{{}^\circ }}=+63.3\,\,kJ$ for the following reaction,$A{{g}_{2}}C{{O}_{3}}(s)r\,2A{{g}^{+}}(aq)+CO_{3}^{2-}(aq)$ the ${{K}_{sp}}$ of $A{{g}_{2}}C{{O}_{3}}(s)$ in water at ${{25}^{o}}C$ is $(R=8.314\,J{{K}^{-1}}\,mo{{l}^{-1}})$

A)
$3.2\times {{10}^{-26}}$

B)
$8.0\times {{10}^{-12}}$

C)
$2.9\times {{10}^{-3}}$

D)
$7.9\times {{10}^{-2}}$

• question_answer67) Which of the following statements is correct for the spontaneous absorption of a gas?               [AIPMT 2014]

A)
$\Delta S$ is negative and therefore, $\Delta H$ should be highly positive

B)
$\Delta S$ is negative and therefore, $\Delta H$ should be highly negative

C)
$\Delta S$ is positive and therefore, $\Delta H$ should be negative

D)
$\Delta S$ is positive and therefore, $\Delta H$ should also be highly positive.

• question_answer68)  For the reaction,${{X}_{2}}{{O}_{4}}(l)\to 2X{{O}_{2}}(g)$ $\Delta U=2.1\,kcal,\,\,\Delta S=20\,cal\,\,{{K}^{-1}}$ at 300 K. Hence, $\Delta G$ is                                                                                               [AIPMT 2014]

A)
2.7 kcal

B)
-2.7 kcal

C)
9.3 kcal

D)
-9.3 kcal

• question_answer69) Which of the following organic compounds has same hybridisation as its combustion product$-(C{{O}_{2}})$?            [AIPMT 2014]

A)
Ethane

B)
Ethyne

C)
Ethene

D)
Ethanol

• question_answer70) Which of the following statements is correct for a reversible process in a state of equilibrium? [NEET 2015 ]

A)
$\Delta G=-2.30\,\,RT\,\,\,\log \,\,K$

B)
$\Delta G=2.30\,\,RT\,\,\,\log \,\,K$

C)
$\Delta {{G}^{o}}=-2.30\,\,RT\,\,\,\log \,\,K$

D)
$\Delta {{G}^{{}^\circ }}=2.30\,\,RT\,\,\,\log \,\,K$

• question_answer71) The heat of combustion of carbon to $C{{O}_{2}}$ is $-393.5\,\,kJ/mol$. The heat released upon the formation of 35.2 g of $C{{O}_{2}}$ from carbon and oxygen gas is                                                      [NEET 2015 (Re)]

A)
- 315 kJ

B)
+ 315 kJ

C)
- 630 kJ

D)
- 3.15 kJ

• question_answer72)  The formation of the oxide ion ${{O}^{2-}}(g),$ from oxygen atom requires first an exothermic and then an endothermic step as shown below,                                                                                           [NEET 2015 (Re)] $O(g)+{{e}^{-}}\to {{O}^{-}}(g);\,\,{{\Delta }_{f}}{{H}^{{}^\circ }}=-141\,\,KJ\,mo{{l}^{-1}}$ ${{O}^{-}}(g)+{{e}^{-}}\xrightarrow{\,}\,{{O}^{2-}}\,(g);\,{{\Delta }_{f}}{{H}^{o}}$$=\,\,+\,780\,\,kJ\,m\,o{{l}^{-1}}$ Thus, process of formation of ${{O}^{2-}}$ in gas phase is unfavourable even though ${{O}^{2-}}$ is isoelectronic with neon. It is due to the fact that

A)
electron repulsion outweighs the stability gained by achieving noble gas configuration

B)
${{O}^{-}}$ ion has comparatively smaller size than oxygen atom

C)
Oxygen is more electronegative

D)
addition of electron in oxygen result in large size of the ion

• question_answer73) The correct thermodynamic conditions for the spontaneous reaction at all temperatures is         [NEET - 2016]

A)
$\Delta H<0$ and $\Delta S=0$

B)
$\Delta H>0$ and $\Delta S<0$

C)
$\Delta H<0$ and $\Delta S>0$

D)
$\Delta H<0$ and $\Delta S<0$

• question_answer74)  Consider the following liquid - vapour equilibrium.                                               [NEET - 2016] $\text{Liquid }\,\text{Vapour}$ Which of the following relations is correct?

A)
$\frac{d\ell nG}{d{{T}^{2}}}=\frac{\Delta {{\Eta }_{v}}}{R{{T}^{2}}}$

B)
$\frac{d\ell nP}{dT}=\frac{-\Delta {{\Eta }_{v}}}{RT}$

C)
$\frac{d\ell nP}{d{{T}^{2}}}=\frac{-\Delta {{\Eta }_{v}}}{{{T}^{2}}}$

D)
$\frac{d\ell nP}{dT}=\frac{\Delta {{\Eta }_{v}}}{R{{T}^{2}}}$

• question_answer75) A gas is allowed to expand in a well-insulated container against a constant external pressure of 2.5 atm from an initial volume of 2.50 L to a final volume of 4.50 L. The change in internal energy $\Delta U$ of the gas in joules will be [NEET-2017]

A)
+505 J

B)
1136.25 J

C)
- 500 J

D)
- 505 J

• question_answer76) For a given reaction, $\Delta H=35.5\,kJ\,mo{{l}^{-1}}$ and $\Delta S=83.6\,J{{K}^{-1}}\,mo{{l}^{-1}}.$ The reaction is spontaneous at : (Assume that $\Delta H$ and $\Delta S$ do not vary with temperature)     [NEET-2017]

A)
$T>298\text{ }K$

B)
$T<425\text{ }K$

C)
$T>425\,K$

D)
All temperatures

• question_answer77) The bond dissociation energies of ${{\text{X}}_{\text{2}}}\text{,}{{\text{Y}}_{\text{2}}}$ and $\text{XY}$ are in the ratio of 1 : 0.5 : 1. $\Delta \text{H}$ for the formation of XY is $\text{--200 kJ mo}{{\text{l}}^{\text{--1}}}$. The bond dissociation energy of ${{\text{X}}_{\text{2}}}$ will be                         [NEET - 2018]

A)
$\text{800 kJ mo}{{\text{l}}^{\text{--1}}}$

B)
$\text{100 kJ mo}{{\text{l}}^{\text{--1}}}$

C)
$\text{200 kJ mo}{{\text{l}}^{\text{--1}}}$

D)
$\text{400 kJ mo}{{\text{l}}^{\text{--1}}}$

• question_answer78) In which case change in entropy is negative?                                                           [NEET 2019]

A)
Sublimation of solid to gas

B)
$2H(g)\to {{H}_{2}}(g)$

C)
Evaporation of water

D)
Expansion of a gas at temperature

• question_answer79) Under isothermal condition, a gas at 300 K expands from 0.1 L to 0.25 L against a constant external pressure of 2 bar. The work done by the gas is [Given that 1 L bar = 100 J]                                            [NEET 2019]

A)
25 J

B)
30 J

C)
-30 J

D)
5 kJ

• question_answer80) For the reaction, $2\,Cl\,(g)\xrightarrow{{}}~C{{l}_{2}}(g)$, the correct option is:                           [NEET 2020]

A)
${{\Delta }_{r}}H>0$ and ${{\Delta }_{r}}S<0$

B)
${{\Delta }_{r}}H<0$ and ${{\Delta }_{r}}S>0$

C)
${{\Delta }_{r}}H<0$ and ${{\Delta }_{r}}S<0$

D)
${{\Delta }_{r}}H>0$ and ${{\Delta }_{r}}S>0$

A)
$q=0,\text{ }\Delta T<0$ and $w>0$

B)
$q<0,\text{ }\Delta T=0$ and $w=0$

C)
$q>0,\text{ }\Delta T>0$ and $w>0$

D)
$q=0,\text{ }\Delta T=0$ and $w=0$