# Solved papers for NEET Chemistry NEET PYQ-Solutions

### done NEET PYQ-Solutions Total Questions - 37

• question_answer1) An organic compound containing C, H and N gave the following results on analysis C = 40%, H = 13.33%, N = 46.67%. Its empirical formula would be:                                [AIPMT 1998]

A)
${{C}_{2}}{{H}_{7}}{{N}_{2}}$

B)
$C{{H}_{5}}N$

C)
$C{{H}_{4}}N$

D)
${{C}_{2}}{{H}_{7}}N$

• question_answer2) A 5% solution of cane sugar (mol. wt. = 342) is isotonic with 1% solution of a substance X. The molecular weight of X is:            [AIPMT 1998]

A)
34.2

B)
171.2

C)
68.4

D)
136.8

• question_answer3) If 0.15 g of solute, dissolved in 15 g of solvent, is boiled at a temperature higher by $0.216{}^\circ C,$ than that of the pure solvent, the molecular weight of the substance is (molal elevation constant for the solvent is $2.16{}^\circ C$):                    [AIPMT 1999]

A)
1.01

B)
10

C)
10.1

D)
100

• question_answer4) The vapour pressure of benzene at a certain temperature is 640 mm. of Hg. A non-volatile and non-electrolyte solid, weighing 2.175 g is added to 39.08 g of benzene. If the vapour pressure of the solution is 600 mm of Hg, what is the molecular weight of solid substance? [AIPMT 1999]

A)
49.50

B)
59.60

C)
69.40

D)
79.82

• question_answer5) In steam distillation of toluene, the pressure of toluene in vapour is:             [AIPMT 2001]

A)
equal pressure of barometer

B)
less than pressure of barometer

C)
equal to vapour pressure to toluene in simple distillation

D)
more than vapour pressure of toluene in simple distillation

• question_answer6) Pure water can be obtained from sea water by: [AIPMT 2001]

A)
centrifugation

B)
plasmolysis

C)
reverse osmosis

D)
sedimentation

• question_answer7) The beans are cooked earlier in pressure cooker, because:                            [AIPMT 2001]

A)
bp increase with increasing pressure

B)
bp decrease with increasing pressure

C)
extra pressure of pressure cooker, softens the beans

D)
internal energy is not lost while cooking in pressure cooker

• question_answer8) A solution contains non-volatile solute of molecular mass ${{M}_{2}}$. Which of the following can be used to calculate the molecular mass of solute in terms of osmotic pressure:      [AIPMT 2002]

A)
${{M}_{2}}=\left[ \frac{{{m}_{2}}}{\pi } \right]\,VRT$

B)
${{M}_{2}}=\left[ \frac{{{m}_{2}}}{V} \right]\frac{RT}{\pi }$

C)
${{M}_{2}}=\left[ \frac{{{m}_{2}}}{V} \right]\pi RT$

D)
${{M}_{2}}=\left[ \frac{{{m}_{2}}}{V} \right]\frac{\pi }{RT}$

• question_answer9) A solution containing components A and B follows Raoult's law:                  [AIPMT 2002]

A)
$A-B$ attraction force is greater than $A-A$and $B-B$

B)
$A-B$  attraction force is less than $A-A$ and  $B-B$

C)
$A-B$ attraction force remains same as $A-A$ and $B-B$

D)
volume of solution is different from sum of volumes of solute and solvent

• question_answer10) The vapour pressure of two liquids P and Q are 80 and 60 torr, respectively. The total vapour pressure of solution obtained by mixing 3 moles of P and 2 moles of Q would be: [AIPMT (S) 2005]

A)
140 torr

B)
20 torr

C)
68 torr

D)
72 torr

• question_answer11) A solution of urea (mol. Mass $56\text{ }g\text{ }mo{{l}^{-1}}$) boils at $100.18{}^\circ C$ at the atmospheric pressure. If ${{K}_{f}}$ and ${{K}_{b}}$ for water are 1.86 and 0.512 K  kg $mo{{l}^{-1}}$ respectively, die above solution will freeze at: [AIPMT (S) 2005]

A)
$-6.54{}^\circ C$

B)
$6.54{}^\circ C$

C)
$0.654{}^\circ C$

D)
$-\text{ }0.654{}^\circ C$

• question_answer12) A solution has a 1 : 4 mole ratio of pentane to hexane. The vapour pressure of the pure hydrocarbons at $20{}^\circ C$ are 440 mm of Hg for pentane and 120 mm of Hg for hexane. The mole fraction of pentarie in the vapour phase would be: [AIPMT (S) 2005]

A)
0.549

B)
0.200

C)
0.786

D)
0.478

• question_answer13) A solution containing 10 g per $d{{m}^{3}}$ of urea (molecular mass $=60\text{ }g\text{ }mo{{l}^{-1}}$) is isotonic with a 5% solution of a non-volatile solute. The molecular mass of this non-volatile solute is:                                        [AIPMT (S) 2006]

A)
$250\text{ }g\text{ }mo{{l}^{-1}}$

B)
$300\text{ }g\text{ }mo{{l}^{-1}}$

C)
$350\text{ }g\text{ }mo{{l}^{-1}}$

D)
$200\text{ }g\text{ }mo{{l}^{-1}}$

• question_answer14) 1.00 g of a non-electrolyte solute (molar mass$250g\text{ }mo{{l}^{-1}}$) was dissolved in 51.2 g of benzene. If the freezing point depression constant, ${{K}_{f}}$ of benzene is $5.12\text{ }K\text{ }kg\text{ }mo{{l}^{-1}},$ the freezing point of benzene will be lowered by:   [AIPMT (S) 2006]

A)
0.4 K

B)
0.3 K

C)
0.5 K

D)
0.2 K

• question_answer15) A solution of acetone in ethanol: [AIPMT (S) 2006]

A)
shows a negative deviation from Raoults law

B)
shows a positive deviation from Raoults law

C)
behaves like a near ideal solution

D)
obeys Raoults law

• question_answer16) During osmosis, flow of water through a semi-permeable membrane is:     [AIPMT (S) 2006]

A)
from solution having higher concentration only

B)
from both sides of semi-permeable membrane with equal flow rates

C)
from both sides of semi-permeable membrane with unequal flow rates

D)
from solution having lower concentration only

• question_answer17) 0.5 molal aqueous solution of a weak acid (HX) is 20% ionised. If ${{K}_{f}}$ for water is $1.86\text{ }K\text{ }kg\text{ }mo{{l}^{-1}},$ the lowering in freezing point of the solution is:                  [AIPMT (S) 2007]

A)
$-1.12\text{ }K$

B)
$0.56\text{ }K$

C)
$1.12\text{ }K$

D)
$-0.56\,K$

• question_answer18) A 0.0020 m aqueous solution of an ionic compound $3.0\times {{10}^{-5}}$ freezes at $0.00732{}^\circ C$. Number of moles of ions which 1 mol of ionic compound produces on being dissolved in water will be $({{K}_{f}}=-1.86{{\,}^{o}}C/m)$[AIPMT (S) 2009]

A)
2

B)
3

C)
4

D)
1

• question_answer19) An aqueous solution is 1.00 molal in KI. Which change will cause the vapour pressure of the solution to increase?               [AIPMT (S) 2010]

A)
Addition of $NaCl$

B)
Addition of $N{{a}_{2}}S{{O}_{4}}$

C)

D)

• question_answer20) A solution of sucrose   (molar mass $=342\text{ }g\text{ }mo{{l}^{-1}}$) has been prepared by dissolving 68.5 g of sucrose in 1000 g of water. The freezing point of the solution obtained will be [AIPMT (S) 2010] (${{K}_{f}}$ for water $=1.86\text{ }K\text{ }kg\text{ }mo{{l}^{-1}}$)

A)
$-0.372{}^\circ C$

B)
$-0.520{}^\circ C$

C)
$+\text{ }0.372{}^\circ C~$

D)
$-\text{ }0.570{}^\circ C$

• question_answer21) The freezing point depression constant for water is $-{{1.86}^{o}}C\,{{m}^{-1}}$. If 5.00 g $N{{a}_{2}}S{{O}_{4}}$ is dissolved in $45.0g\,{{H}_{2}}O,$ the freezing point is changed by $-3.82{}^\circ C$. Calculate the van't Hoff factor for$N{{a}_{2}}S{{O}_{4}}$.               [AIPMT (S) 2011]

A)
2.63

B)
3.11

C)
0.381

D)
2.05

• question_answer22) The van't Hoff factor, i for a compound which undergoes dissociation in one solvent and association in other solvent is respectively. [AIPMT (S) 2011]

A)
less than one and less than one

B)
greater than one and less than one

C)
greater than one and greater than one

D)
less than one and greater than one

• question_answer23) A 0.1 molal aqueous solution of a weak acid is 30% ionised. If ${{K}_{f}}$ for water is $1.86{}^\circ C/m,$ the freezing point of the solution will be [AIPMT (M) 2011]

A)
$\text{ }0.18{}^\circ C$

B)
$\text{ }0.54{}^\circ C~$

C)
$\text{ }0.36{}^\circ C$

D)
$\text{ }0.24{}^\circ C$

• question_answer24) 200 mL of an aqueous solution of a protein contains its 1.26 g. The osmotic pressure of this solution at 300 K is found to be $2.57\times {{10}^{-3}}$bar. The molar mass of protein will be    (R = 0.083 L bar $mo{{l}^{-1}}$)    [AIPMT (M) 2011]

A)
$51022\text{ }g\text{ }mo{{l}^{-1}}$

B)
$122044\text{ }g\text{ }mo{{l}^{-1}}$

C)
$31011\text{ }g\text{ }mo{{l}^{-1}}$

D)
$61038\text{ }g\text{ }mo{{l}^{-1}}$

• question_answer25) ${{p}_{A}}$ and ${{p}_{B}}$ are the vapour pressure of pure liquid components, A and B, respectively of an ideal binary solution. If ${{x}_{A}}$ represents the mole fraction of component A, the total pressure of the solution will be [AIPMT (S) 2012]

A)
${{p}_{A}}+{{x}_{A}}({{p}_{B}}-{{p}_{A}})$

B)
${{p}_{A}}+{{x}_{A}}({{p}_{A}}-{{p}_{B}})$

C)
${{p}_{B}}+{{x}_{A}}({{p}_{B}}-{{p}_{A}})$

D)
${{p}_{B}}+{{x}_{A}}({{p}_{A}}-{{p}_{B}})$

• question_answer26) Vapour pressure of chloroform $(CHC{{l}_{3}})$ and dichloromethane $(C{{H}_{2}}C{{l}_{2}})$ at $25{}^\circ C$ are 200 mmHg and 41.5 mmHg respectively. Vapour pressure of the solution obtained by mixing 25.5 g of $CHC{{l}_{3}}$ and 40 g of $C{{H}_{2}}C{{l}_{2}}$ at the same temperature will be (Molecular mass of $CHC{{l}_{3}}=119.5\,u$ and molecular mass of $C{{H}_{2}}C{{l}_{2}}=85\,u$)[AIPMT (M) 2012]

A)
173.9 mmHg

B)
615.0 mmHg

C)
347.9 mmHg

D)
None of these

• question_answer27) Of the following 0.10 m aqueous solutions, which one will exhibit the largest freezing point depression? [AIPMT 2014]

A)
KCl

B)

C)

D)
${{K}_{2}}S{{O}_{4}}$

• question_answer28) Which one is not equal to zero for an ideal solution?                              [NEET 2015 ]

A)
$\Delta {{H}_{mix}}$

B)
$\Delta {{S}_{mix}}$

C)
$\Delta {{V}_{mix}}$

D)
$\Delta P={{P}_{observed}}-\,{{P}_{Raoult}}$

• question_answer29) The boiling point of $0.2\,\,mol\,\,k{{g}^{-1}}$ solution of X in water is greater than equimolal solution of Y in water. Which one of the following statements is true in this case?                     [NEET 2015 ]

A)
X is undergoing dissociation in water.

B)
Molecular mass of X is greater than the molecular mass of V.

C)
Molecular mass of X is less than the molecular mass of V.

D)
V is undergoing dissociation in water while X undergoes no change.

• question_answer30) Which one of the following electrolytes has the same value of van't Hoffs factor (2) as that of $A{{l}_{2}}{{\left( S{{O}_{4}} \right)}_{3}}$ (if all are 100% ionised)? [NEET 2015 ]

A)
${{K}_{2}}S{{O}_{4}}$

B)
${{K}_{3}}[Fe{{(CN)}_{6}}]$

C)
$Al{{(N{{O}_{3}})}_{3}}$

D)
${{K}_{4}}[Fe{{(CN)}_{6}}]$

• question_answer31) Which of the following statement about the composition of the vapour over an ideal a 1 : 1 molar mixture of benzene and toluene is correct?  Assume that the temperature is constant at $25{{\,}^{o}}C.$  (Given : Vapour Pressure Data at ${{25}^{o}}C,$ benzene = 12.8 kPa, Toluene = 3.85 kPa) [NEET - 2016]

A)
The vapour will contain a higher percentage of benzene

B)
The vapour will contain a higher percentage of toluene

C)
The vapour will contain equal amounts of benezene and toluene

D)
Not enough information is given to make a predication

• question_answer32) At ${{100}^{o}}C$ the vapour pressure of a solution of 6.5g of a solute in 100 g water is 732 mm. If ${{K}_{b}}=0.52,$ the boiling point of this solution will be :-                                       [NEET - 2016]

A)
${{101}^{o}}C$

B)
${{100}^{o}}C$

C)
${{102}^{o}}C$

D)
${{103}^{o}}C$

• question_answer33) If molality of the dilute solution is doubled, the value of molal depression constant $({{K}_{f}})$ will be [NEET-2017]

A)
Unchanged

B)
Doubled

C)
Halved

D)
Tripled

• question_answer34) For an ideal solution, the correct option is- [NEET 2019]

A)
${{\Delta }_{mix}}$H = 0 at constant T and P

B)
${{\Delta }_{\min }}$G = 0 at constant T and P

C)
${{\Delta }_{mix}}$ S = 0 at constant T and P

D)
${{\Delta }_{mix}}$ $V\ne 0$at constant T and P

• question_answer35) The mixture that forms maximum boiling azeotrope is:                                  [NEET 2019]

A)
Acetone + Carbon disulphide

B)
Heptane + Octane

C)
Water + Nitric acid

D)
Ethanol + Water

• question_answer36) The freezing point depression constant $(Kf)$of benzene is $5.12\text{ }K\text{ }kg\text{ }mo{{l}^{1}}$. The freezing point depression for the solution of molality 0.078 m containing a non-electrolyte solute in benzene is (rounded off upto two decimal places): [NEET 2020]

A)
0.80 K

B)
0.40 K

C)
0.60 K

D)
0.20 K

• question_answer37) The mixture which shows positive deviation from Raoults law is                               [NEET 2020]

A)
Benzene + Toluene

B)
Acetone + Chloroform

C)
Chloroethane + Bromoethane

D)
Ethanol + Acetone