Solutions · JEE Main previous year questions

Given below are two statements: One is labelled as Assertion A and the other is labelled as Reason R. Assertion A: Butan -1- ol has higher boiling point than ethoxyethane. Reason R: Extensive hydrogen bonding leads to stronger association of molecules. In the light of the above statements, choose the correct answer from the options given below:

1. A.A is false but R is true
2. B.Both A and R are true but R is not the correct explanation of A
3. C.Both A and R are true and R is the correct explanation of A
4. D.A is true but R is false

If the boiling points of two solvents X and Y (having same molecular weights) are in the ratio $2:1$ and their enthalpy of vaporizations are in the ratio $1:2$, then the boiling point elevation constant of X is $\underline{\text{m}}$ times the boiling point elevation constant of Y. The value of m is ____ (nearest integer)

1. A.A and B only
2. B.A, C & D only
3. C.B, C & D only
4. D.C and D only

$25\text{ mL}$ of an aqueous solution of $\text{KCl}$ was found to require $20\text{ mL}$ of $1\text{ M }{\text{AgNO}}_3$ solution when titrated using ${\text{K}}_2{\text{CrO}}_4$ as an indicator. What is the depression in freezing point of $\text{KCl}$ solution of the given concentration? ________ (Nearest integer). (Given : ${\text{K}}_f=2.0{\text{ K kg mol}}^{-1}$) Assume 1) $100\%$ ionization and 2) density of the aqueous solution as $1{\text{ g mL}}^{-1}$

At $27^{\circ }\text{C}$, a solution containing $2.5\text{ g}$ of solute in $250.0\text{ mL}$ of solution exerts an osmotic pressure of $400\text{ Pa}$. The molar mass of the solute is ___________ ${\text{g mol}}^{-1}$ (Nearest integer) (Given : $\mathrm{R}=0.083{\text{ L bar K}}^{-1}{\text{ mol}}^{-1}$)

Evaluate the following statements for their correctness. A. The elevation in boiling point temperature of water will be same for $0.1\mathrm{M}\mathrm{NaCl}$ and $0.1\mathrm{M}$ urea. B. Azeotropic mixtures boil without change in their composition. C. Osmosis always takes place from hypertonic to hypotonic solution. D. The density of $32\%{\mathrm{H}}_2{\mathrm{SO}}_4$ solution having molarity $4.09\text{ M}$ is approximately $1.26{\text{ g mL}}^{-1}$ E. A negatively charged sol is obtained when $\mathrm{KI}$ solution is added to silver nitrate solution. Choose the correct answer from the options given below :

1. A.A, B and D only
2. B.A and C only
3. C.B and D only
4. D.B, D and E only

1. A.(A), (B) and (E) only
2. B.(A), (C) and (D) only
3. C.(A), (C) and (E) only
4. D.(B), (C) and (D) only

Match List I with List II $$\begin{array}{llll}& \text{List I}& & \text{List II}\\ \text{A.}& \text{van’t Hoff factor, i}& \text{I.}& \text{Cryoscopic constant}\\ \text{B.}& {\mathrm{k}}_{\mathrm{f}}& \text{II.}& \text{Isotonic solutions}\\ \text{C.}& \text{Solutions with same osmotic pressure}& \text{III.}& \frac{\text{Normal molar mass}}{\text{Abnormal molar mass}}\\ \text{D.}& \text{Azeotropes}& \text{IV.}& \text{Solutions with same composition of vapour above it}\end{array}$$ Choose the correct answer from the options given below :

1. A.A-III, B-I, C-IV, D-II
2. B.A-III, B-I, C-II, D-IV
3. C.A-III, B-II, C-I, D-IV
4. D.A-I, B-III, C-II, D-IV

The number of pairs of the solutions having the same value of the osmotic pressure from the following is ____. (Assume 100% ionization) A. 0.500 $\mathrm{M}{\mathrm{C}}_2{\mathrm{H}}_5\mathrm{OH}(\mathrm{aq})$ and 0.25 $\mathrm{M}\mathrm{KBr}(\mathrm{aq})$ B. 0.100 $\mathrm{M}{\mathrm{K}}_4[\mathrm{Fe}(\mathrm{CN}{)}_6](\mathrm{aq})$ and 0.100 $\mathrm{M}\mathrm{FeS}{\mathrm{O}}_4(\mathrm{N}{\mathrm{H}}_4{)}_2\mathrm{S}{\mathrm{O}}_4(\mathrm{aq})$ C. 0.05 $\mathrm{M}{\mathrm{K}}_4[\mathrm{Fe}(\mathrm{CN}{)}_6](\mathrm{aq})$ and 0.25 $\mathrm{M}\mathrm{NaCl}(\mathrm{aq})$ D. 0.15 $\mathrm{M}\mathrm{NaCl}(\mathrm{aq})$ and 0.1 $\mathrm{M}\mathrm{BaC}{\mathrm{l}}_2(\mathrm{aq})$ E. 0.02 $\mathrm{M}KCl.MgC{\mathrm{l}}_2.6{\mathrm{H}}_2\mathrm{O}(\mathrm{aq})$ and 0.05 $\mathrm{M}\mathrm{KCl}(\mathrm{aq})$

In the depression of freezing point experiment A. Vapour pressure of the solution is less than that of pure solvent B. Vapour pressure of the solution is more than that of pure solvent C. Only solute molecules solidify at the freezing point D. Only solvent molecules solidify at the freezing point Choose the most appropriate answer from the options given below :

1. A.A and C only
2. B.A only
3. C.A and D only
4. D.B and C only

Statement I : For colloidal particles, the values of colligative properties are of small order as compared to values shown by true solutions at same concentration. Statement II : For colloidal particles, the potential difference between the fixed layer and the diffused layer of same charges is called the electrokinetic potential or zeta potential. In the light of the above statements, choose the correct answer from the options given below

1. A.Both Statement I and Statement II are false
2. B.Statement I is true and Statement II is false
3. C.Both Statement I and Statement II are true
4. D.Statement I is false but Statement II is true

$1.80\mathrm{g}$ of solute A was dissolved in $62.5\mathrm{c}{\mathrm{m}}^3$ of ethanol and freezing point of the solution was found to be $155.1\mathrm{K}$. The molar mass of solute A is ____ $\mathrm{g}\mathrm{mo}{\mathrm{l}}^{-1}$. [Given : Freezing point of ethanol is $156.0\mathrm{K}$. Density of ethanol is $0.80\mathrm{g}\mathrm{c}{\mathrm{m}}^{-3}$. Freezing point depression constant of ethanol is $2.00\mathrm{K}\mathrm{kg}\mathrm{mo}{\mathrm{l}}^{-1}$]

$150\text{ g}$ of acetic acid was contaminated with $10.2\text{ g}$ ascorbic acid (${\text{C}}_6{\text{H}}_8{\text{O}}_6$) to lower down its freezing point by $(x\times 10^{-1}{)}^{\circ }\text{C}$. The value of $x$ is _________. (Nearest integer) [Given ${\text{K}}_f=3.9{\text{ K kg mol}}^{-1}$; molar mass of ascorbic acid $=176{\text{ g mol}}^{-1}$]

Boiling point of a $2\%$ aqueous solution of a non-volatile solute A is equal to the boiling point of $8\%$ aqueous solution of a non-volatile solute B. The relation between molecular weights of A and B is

1. A.${\mathrm{M}}_A=4{\mathrm{M}}_B$
2. B.${\mathrm{M}}_B=4{\mathrm{M}}_A$
3. C.${\mathrm{M}}_A=8{\mathrm{M}}_B$
4. D.${\mathrm{M}}_B=8{\mathrm{M}}_A$

Two solutions A and B are prepared by dissolving 1 g of non-volatile solutes X and Y, respectively in 1 kg of water. The ratio of depression in freezing points for A and B is found to be 1 : 4. The ratio of molar masses of X and Y is

1. A.1 : 4
2. B.1 : 0.25
3. C.1 : 0.20
4. D.1 : 5

$2.5\mathrm{g}$ of protein containing only glycine (${\mathrm{C}}_2{\mathrm{H}}_5\mathrm{N}{\mathrm{O}}_2$) is dissolved in water to make $500\mathrm{mL}$ of solution. The osmotic pressure of this solution at $300\mathrm{K}$ is found to be $5.03\times 10^{-3}\mathrm{bar}$. The total number of glycine units present in the protein is ____. (Given : $\mathrm{R}=0.083\mathrm{L}\mathrm{bar}{\mathrm{K}}^{-1}\mathrm{mo}{\mathrm{l}}^{-1}$)

$2\mathrm{g}$ of a non-volatile non-electrolyte solute is dissolved in $200\mathrm{g}$ of two different solvents A and B whose ebullioscopic constants are in the ratio of $1:8$. The elevation in boiling points of A and B are in the ratio $\frac{x}{y}(x:y)$. The value of $y$ is ____. (Nearest integer)

A solution containing $2.5\times 10^{-3}\text{ kg}$ of a solute dissolved in $75\times 10^{-3}\text{ kg}$ of water boils at $373.535\text{ K}$. The molar mass of the solute is ________ ${\text{g mol}}^{-1}$. [nearest integer] (Given : ${\text{K}}_b({\text{H}}_2\text{O})=0.52{\text{ K kg mol}}^{-1}$ and boiling point of water $=373.15\text{ K}$)

The osmotic pressure exerted by a solution prepared by dissolving $2.0\mathrm{g}$ of protein of molar mass $60\mathrm{kg}\mathrm{mo}{\mathrm{l}}^{-1}$ in $200\mathrm{mL}$ of water at $27^{\circ }\mathrm{C}$ is ____ $\mathrm{Pa}$. [integer value] (use $\mathrm{R}=0.083\mathrm{L}\mathrm{bar}\mathrm{mo}{\mathrm{l}}^{-1}{\mathrm{K}}^{-1}$)

Solute A associates in water. When $0.7\mathrm{g}$ of solute A is dissolved in $42.0\mathrm{g}$ of water, it depresses the freezing point by $0.2^{\circ }\mathrm{C}$. The percentage association of solute A in water, is : [Given : Molar mass of $\mathrm{A}=93\mathrm{g}\mathrm{mo}{\mathrm{l}}^{-1}$. Molal depression constant of water is $1.86\mathrm{K}\mathrm{kg}\mathrm{mo}{\mathrm{l}}^{-1}$.]

1. A.50%
2. B.60%
3. C.70%
4. D.80%

83 g of ethylene glycol dissolved in 625 g of water. The freezing point of the solution is ___________ K. (Nearest integer) [$\text{Use : Molal Freezing point depression constant of water}=1.86{\text{ K kg mol}}^{-1}$ Freezing Point of water $=273\text{ K}$ $\text{Atomic masses : C : }12.0\text{ u}$, $\mathrm{O}:16.0\text{ u}$, $\mathrm{H}:1.0\text{ u}$]

In a solvent 50% of an acid HA dimerizes and the rest dissociates. The van't Hoff factor of the acid is __________ $\times 10^{-2}$. (Round off to the nearest integer)

When 3.00 g of a substance 'X' is dissolved in 100 g of $\mathrm{CC}{\mathrm{l}}_4$, it raises the boiling point by 0.60 K. The molar mass of the substance 'X' is ____ $\mathrm{g}\mathrm{mo}{\mathrm{l}}^{-1}$. (Nearest integer). [Given $K_b$ for $\mathrm{CC}{\mathrm{l}}_4$ is 5.0 K kg $\mathrm{mo}{\mathrm{l}}^{-1}$]