# NEET

Explore popular questions from Solutions for NEET. This collection covers Solutions previous year NEET questions hand picked by experienced teachers.

## Biology

Solutions

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Q 1. If molality of the dilute solution is doubled, the value of molal depression constant {tex} \left( K _ { \rho } \right) {/tex} will be

A

halved

B

tripled

unchanged

D

doubled

##### Explanation

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Q 2. Which of the following is dependent on temperature?

Molarity

B

Mole fraction

C

Weight percentage

D

Molality

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Q 3. Which one of the following is incorrect for ideal solution?

A

{tex} \Delta H _ { \operatorname { mix } } = 0 {/tex}

B

{tex} \Delta U _ { \operatorname { mix } } = 0 {/tex}

C

{tex} \Delta P = P _ { \text {obs } } - P _ { \text {calculated by Raorit's law } } = 0 {/tex}

{tex} \Delta G _ { \operatorname { mix } } = 0 {/tex}

##### Explanation

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Q 4. Which of the following statements about the composition of the vapour over an ideal {tex} 1 : 1 {/tex} molar mixture of benzene and toluene is correct? Assume that the temperature is constant at {tex} 25 ^ { \circ } \mathrm { C } {/tex} . (Given, vapour pressure data at {tex} 25 ^ { \circ } \mathrm { C } , {/tex} benzene {tex} = 12.8 \mathrm { kPa } {/tex} , toluene {tex} = 3.85 \mathrm { kPa } {/tex} )

A

The vapour will contain equal amounts of benzene and toluene.

B

Not enough information is given to make a prediction.

The vapour will contain a higher percentage of benzene.

D

The vapour will contain a higher
percentage of toluene.

##### Explanation

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Q 5. At {tex} 100 ^ { \circ } \mathrm { C } {/tex} the vapour pressure of a solution of {tex}6.5 \,\mathrm { g } {/tex} of a solute in {tex}100\, \mathrm { g } {/tex} water is {tex}732\, \mathrm { mm } {/tex} . If {tex}K _ { b } = 0.52 , {/tex} the boiling point of this solution will be

A

{tex} 102 ^ { \circ } \mathrm { C } {/tex}

B

{tex} 103 ^ { \circ } \mathrm { C } {/tex}

{tex} 101 ^ { \circ } \mathrm { C } {/tex}

D

{tex} 100 ^ { \circ } \mathrm { C } {/tex}

##### Explanation

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Q 6. The boiling point of {tex}0.2\, \mathrm { mol } \mathrm { kg } ^ { - 1 } {/tex} solution of {tex} X {/tex} in water is greater than equimolal solution of {tex} Y {/tex} in water. Which one of the following statements is true in this case?

A

Molecular mass of {tex} X {/tex} is less than the molecular mass of {tex} Y {/tex} .

B

{tex} Y {/tex} is undergoing dissociation in water while {tex} X {/tex} undergoes no change.

{tex} X {/tex} is undergoing dissociation in water.

D

Molecular mass of {tex} X {/tex} is greater than the
molecular mass of {tex} Y {/tex}

##### Explanation

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Q 7. Which one of the following electrolytes has the same value of van't Hoff factor {tex} ( i ) {/tex} as that of {tex} \mathrm { Al } _ { 2 } \left( \mathrm { SO } _ { 4 } \right) _ { 3 } {/tex} (if all are 100{tex} \% {/tex} ionised)?

A

{tex} \mathrm { Al } \left( \mathrm { NO } _ { 3 } \right) _ { 3 } {/tex}

{tex} \mathrm { K } _ { 4 } \left[ \mathrm { Fe } ( \mathrm { CN } ) _ { 6 } \right] {/tex}

C

{tex} \mathrm { K } _ { 2 } \mathrm { SO } _ { 4 } {/tex}

D

{tex} \mathrm { K } _ { 3 } \left[ \mathrm { Fe } ( \mathrm { CN } ) _ { 6 } \right] {/tex}

##### Explanation

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Q 8. Which of them is not equal to zero for an ideal solution?

A

{tex} \Delta V _ { \operatorname { mix } } {/tex}

B

C

{tex} \Delta H _ { \mathrm { min } } {/tex}

{tex} \Delta S _ { mix } {/tex}

##### Explanation

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Q 9. Of the following {tex} 0.10\,\mathrm { m } {/tex} aqueous solutions, which one will exhibit the largest freezing point depression?

A

{tex} \mathrm { KCl } {/tex}

B

{tex} \mathrm { C } _ { 6 } \mathrm { H } _ { 12 } \mathrm { O } _ { 6 } {/tex}

{tex} \mathrm { Al } _ { 2 } \left( \mathrm { SO } _ { 4 } \right) _ { 3 } {/tex}

D

{tex} \mathrm { K } _ { 2 } \mathrm { SO } _ { 4 } {/tex}

##### Explanation

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Q 10. How many grams of concentrated nitric acid solution should be used to prepare {tex} 250\,\mathrm { mL } {/tex} of {tex} 2.0\,\mathrm { M }\,\, \mathrm { HNO } _ { 3 } ? {/tex} The concentrated acid is {tex} 70\% \mathrm { HNO } _ { 3 } {/tex}

A

70.0{tex} \mathrm { g } {/tex} conc. {tex} \mathrm { HNO } _ { 3 } {/tex}

B

{tex} 54.0\,\mathrm { g } {/tex} conc. HNO {tex} _ { 3 } {/tex}

45.0{tex} \mathrm { g } {/tex} conc. {tex} \mathrm { HNO } _ { 3 } {/tex}

D

90.0{tex} \mathrm { g } {/tex} conc. HNO {tex} _ { 3 } {/tex}

##### Explanation

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Q 11. Which condition is not satisfied by an ideal solution?

A

{tex} \Delta _ { \operatorname { mix } } V = 0 {/tex}

{tex} \Delta _ { \operatorname { mix } } S = 0 {/tex}

C

Obeyance to Raoult's Law

D

{tex} \Delta _ { \operatorname { mix } } H = 0 {/tex}

##### Explanation

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Q 12. {tex} p _ { A } {/tex} and {tex} p _ { B } {/tex} are the vapour pressure of pure liquid components, {tex} A {/tex} and {tex} B , {/tex} respectively of an ideal binary solution. If {tex} x _ { A } {/tex} represents the mole fraction of component {tex} A , {/tex} the total pressure of the solution will be

A

{tex} p _ { A } + x _ { A } \left( p _ { B } - p _ { A } \right) {/tex}

B

{tex} p _ { A } + x _ { A } \left( p _ { A } - p _ { B } \right) {/tex}

C

{tex} p _ { B } + x _ { A } \left( p _ { B } - p _ { A } \right) {/tex}

{tex} p _ { B } + x _ { A } \left( p _ { A } - p _ { B } \right) {/tex}

##### Explanation

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Q 13. Vapour pressure of chloroform {tex} \left( \mathrm { CHCl } _ { 3 } \right) {/tex} and dichloromethane {tex} \left( \mathrm { CH } _ { 2 } \mathrm { Cl } _ { 2 } \right) {/tex} at {tex} 25 ^ { \circ } \mathrm { C } {/tex} are {tex} \mathrm 200\,{ mm } {/tex} Hg and 41.5{tex} \mathrm { mm } {/tex} Hg respectively. Vapour pressure of the solution obtained by mixing 25.5{tex} \mathrm { g } {/tex} of {tex} \mathrm { CHCl } _ { 3 } {/tex} and 40{tex} \mathrm { g } {/tex} of {tex} \mathrm { CH } _ { 2 } \mathrm { Cl } _ { 2 } {/tex} at the same temperature will be (Molecular mass of {tex} \mathrm { CH } \mathrm { Cl } _ { 3 } = 119.5 \mathrm { u } {/tex} and {tex} \left. \text { molecular mass of } \mathrm { CH } _ { 2 } \mathrm { Cl } _ { 2 } = 85 \mathrm { u } \right) {/tex}

A

{tex} 173.9\,\mathrm { mm } \mathrm { Hg } {/tex}

{tex}90.63\, \mathrm { mm } \mathrm { Hg } {/tex}

C

{tex}347.9\, \mathrm { mm } \mathrm { Hg } {/tex}

D

{tex}285.5\, \mathrm { mm } \mathrm { Hg } {/tex}

##### Explanation

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Q 14. {tex}200\, \mathrm { mL } {/tex} of an aqueous solution of a protein contains its {tex}1.26\, \mathrm { g } {/tex} . The osmotic pressure of this solution at {tex} 300\,\mathrm { K } {/tex} is found to be {tex} 2.57 \times 10 ^ { - 3 } \mathrm { bar } {/tex} . The molar mass of protein will be {tex} \left( R = 0.083 \mathrm { L } \text { bar mol } ^ { - 1 } \mathrm { K } ^ { - 1 } \right) {/tex}

A

{tex} 51022\,\mathrm { g } \,\mathrm { mol } ^ { - 1 } {/tex}

B

{tex}122044\, \mathrm { g }\, \mathrm { mol } ^ { - 1 } {/tex}

C

{tex}31011 \,g\, \mathrm { mol } ^ { - 1 } {/tex}

{tex}61038\, \mathrm { g } \mathrm { mol } ^ { - 1 } {/tex}

##### Explanation

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Q 15. An aqueous solution is 1.00 molal in KI. Which change will cause the vapour pressure of the solution to increase?

A

B

Addition of {tex} \mathrm { Na } _ { 2 } \mathrm { SO } _ { 4 } {/tex}

C

Addition of 1.00 molal {tex} \mathrm { KI } {/tex}

##### Explanation

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Q 16. A solution of sucrose{tex} \left. \text { (molar mass } = 342\, \mathrm { g }\, \mathrm { mol } ^ { - 1 } \right) {/tex} has been prepared by dissolving 68.5{tex} \mathrm { g } {/tex} of sucrose in 1000{tex} \mathrm { g } {/tex} of water. The freezing point of the solution obtained will be {tex} \left( K _ { f } \text { for water } \right. {/tex} {tex} \left. = 1.86 \mathrm { K } \text { kg mol } ^ { - 1 } \right) {/tex}

{tex} - 0.372 ^ { \circ } \mathrm { C } {/tex}

B

{tex} - 0.520 ^ { \circ } \mathrm { C } {/tex}

C

{tex} + 0.372 ^ { \circ } \mathrm { C } {/tex}

D

{tex} - 0.570 ^ { \circ } \mathrm { C } {/tex}

##### Explanation

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Q 17. Concentrated aqueous sulphuric acid is {tex}98 \% \,\mathrm { H } _ { 2 } \mathrm { SO } _ { 4 } {/tex} by mass and has a density of {tex}1.80\, \mathrm { g } \,\mathrm { mL } ^ { - 1 } {/tex} . Volume of acid required to make one litre of {tex}0.1\, \mathrm { M } \mathrm { H } _ { 2 } \mathrm { SO } _ { 4 } {/tex} solution is

A

{tex}16.65\, \mathrm { mL } {/tex}

B

{tex}22.20\, \mathrm { mL } {/tex}

{tex} 5.55\,\mathrm { mL } {/tex}

D

{tex}11.10\, \mathrm { mL } {/tex}

##### Explanation

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Q 18. During osmosis, flow of water through a semipermeable membrane is

A

from solution having lower concentration only

B

from solution having higher concentration only

C

from both sides of semipermeable membrane with equal flow rates

from both sides of semipermeable membrane with unequal flow rates.

##### Explanation

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Q 19. A solution of acetone in ethanol

A

obeys Raoult's law

B

shows a negative deviation from Raoult's law

shows a positive deviation from Raoult's law

D

behaves like a near ideal solution.

##### Explanation

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Q 20. {tex} 1.000\,\mathrm { g } {/tex} of a non-electrolyte solute (molar mass {tex} \left. 250 \mathrm { g } \mathrm { mol } ^ { - 1 } \right) {/tex} was dissolved in 51.2{tex} \mathrm { g } {/tex} of benzene. If the freezing point depression constant, {tex} K _ { f } {/tex} of benzene is {tex} 5.12 \mathrm { K } \mathrm { kg } \mathrm { mol } ^ { - 1 } , {/tex} the freezing point of benzene will be lowered by

A

{tex}0.2\, \mathrm { K } {/tex}

{tex}0.4\, \mathrm { K } {/tex}

C

{tex}0.3\, \mathrm { K } {/tex}

D

{tex}0.5\, \mathrm { K } {/tex}

##### Explanation

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Q 21. The mole fraction of the solute in one molal aqueous solution is

A

0.009

0.018

C

0.027

D

0.036

##### Explanation

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Q 22. The vapour pressure of two liquids {tex} P {/tex} and {tex} Q {/tex} are 80 and 60 torr, respectively. The total vapour pressure of solution obtained by mixing 3 mole of {tex} P {/tex} and 2 mol of {tex} Q {/tex} would be

72 torr

B

140 torr

C

68 tor

D

20 torr

##### Explanation

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Q 23. A solution has a {tex} 1 : 4 {/tex} mole ratio of pentane to hexane. The vapour pressures of the pure hydrocarbons at {tex} 20 ^ { \circ } \mathrm { C } {/tex} are {tex}440\, \mathrm { mm } {/tex} Hg for pentane and {tex}120\, \mathrm { mm } {/tex} Hg for hexane. The mole fraction of pentane in the vapour phase would be

A

0.2

B

0.549

C

0.786

0.478

##### Explanation

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Q 24. A solution of urea{tex} \left. \text { (mol. mass } 56 \mathrm { g } \mathrm { mol } ^ { - 1 } \right) {/tex} boils at {tex} 100.18 ^ { \circ } \mathrm { C } {/tex} at the atmospheric pressure. If {tex} K _ { f } {/tex} and {tex} K _ { b } {/tex} for water are 1.86 and {tex}0.512\, \mathrm { K } \,\mathrm { kg } \,\mathrm { mol } ^ { - 1 } {/tex} respectively, the above solution will freeze at

A

{tex} 0.654 ^ { \circ } \mathrm { C } {/tex}

{tex} - 0.654 ^ { \circ } \mathrm { C } {/tex}

C

{tex} 6.54 ^ { \circ } \mathrm { C } {/tex}

D

{tex} - 6.54 ^ { \circ } \mathrm { C } {/tex}

##### Explanation

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Q 25. A solution contains non volatile solute of molecular mass {tex} M _ { 2 } . {/tex} Which of the following can be used to calculate the molecular mass of solute in terms of osmotic pressure?

A

{tex} M _ { 2 } = \left( \frac { m _ { 2 } } { \pi } \right) V R T {/tex}

{tex} M _ { 2 } = \left( \frac { m _ { 2 } } { V } \right) \frac { R T } { \pi } {/tex}

C

{tex} M _ { 2 } = \left( \frac { m _ { 2 } } { V } \right) \pi R T {/tex}

D

{tex} M _ { 2 } = \left( \frac { m _ { 2 } } { V } \right) \frac { \pi } { R T } {/tex}