Solutions · JEE Main previous year questions

Given below are two statements : Given : Molar mass of C, H, O, Cl are 12, 1, 16 and $35.5\mathrm{g}\mathrm{mo}{\mathrm{l}}^{-1}$, respectively Statement I : In $30\%$ (w/w) solution of methanol in $\mathrm{CC}{\mathrm{l}}_4(\text{at T K})$, the mole fraction of $\mathrm{CC}{\mathrm{l}}_4$ is equal to 0.33. Statement II : Mixture of methanol and $\mathrm{CC}{\mathrm{l}}_4$ shows positive deviation from Raoult's law. 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 true
2. B.Both Statement I and Statement II are false
3. C.Statement I is true but Statement II is false
4. D.Statement I is false but Statement II is true

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

Given below are two statements : Statement I : Vapours of the liquid with higher boiling point condense before vapours of the liquid with lower boiling points in fractional distillation. Statement II : The vapours rising up in the fractionating column become richer in high boiling component of the mixture. 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 true
2. B.Both Statement I and Statement II are false
3. C.Statement I is true but Statement II is false
4. D.Statement I is false but Statement II is true

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

Arrange the following compounds according to increasing order of boiling points. $\mathrm{n}-{\mathrm{C}}_4{\mathrm{H}}_9\mathrm{OH}$ (A), $\mathrm{n}-{\mathrm{C}}_4{\mathrm{H}}_9\mathrm{N}{\mathrm{H}}_2$ (B), $\mathrm{n}-{\mathrm{C}}_4{\mathrm{H}}_{10}$ (C) and ${\mathrm{C}}_2{\mathrm{H}}_5\mathrm{NH}{\mathrm{C}}_2{\mathrm{H}}_5$(D).

1. A.$\mathrm{C}<\mathrm{B}<\mathrm{A}<\mathrm{D}$
2. B.$\mathrm{D}<\mathrm{C}<\mathrm{B}<\mathrm{A}$
3. C.$\mathrm{C}<\mathrm{D}<\mathrm{B}<\mathrm{A}$
4. D.$\mathrm{D}<\mathrm{B}<\mathrm{A}<\mathrm{C}$

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

Match List - I with List - II. $$\begin{array}{ll}\text{List - I}& \text{List - II}\\ \text{Purification technique}& \text{Used to separate}\\ \text{A. Simple distillation}& \text{I. Steam volatile compound}\\ \text{B. Fractional distillation}& \text{II. Two liquids with large difference in boiling points}\\ \text{C. Steam distillation}& \text{III. Liquid decomposing at its boiling point}\\ \text{D. Distillation under reduced pressure}& \text{IV. Two liquids with close boiling points}\end{array}$$ Choose the $\underline{\text{correct}}$ answer from the options given below :

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

A non-volatile, non-electrolyte solid solute when dissolved in $40\mathrm{g}$ of a solvent, the vapour pressure of the solvent decreased from $760\mathrm{mm}\mathrm{Hg}$ to $750\mathrm{mm}\mathrm{Hg}$. If the same solution boils at $320\mathrm{K}$, then the number of moles of the solvent present in the solution is ____. (Nearest integer) [Given: boiling point of the pure solvent = $319.5\mathrm{K}$, ${\mathrm{K}}_{\mathrm{b}}$ of the solvent = $0.3\mathrm{K}\mathrm{kg}\mathrm{mo}{\mathrm{l}}^{-1}$]

$19.5\mathrm{g}$ of fluoro acetic acid (molar mass $=78\mathrm{g}\mathrm{mo}{\mathrm{l}}^{-1}$) is dissolved in $500\mathrm{g}$ of water at $298\mathrm{K}$. The depression in the freezing point of water was $1^{\circ }\mathrm{C}$. What is $K_{\mathrm{a}}$ of fluoro acetic acid ? (For water, $K_{\mathrm{f}}=1.86\mathrm{K}\mathrm{kg}\mathrm{mo}{\mathrm{l}}^{-1}$). Assume molarity and molality to have same values.

1. A.$10^{-6}$
2. B.$4\times 10^{-4}$
3. C.$3\times 10^{-5}$
4. D.$3\times 10^{-3}$

Given below are two statements : Statement (I) : 1,2,3-Trihydroxypropane can be separated from water by simple distillation. Statement (II) : An azeotropic mixture cannot be separated by fractional distillation. 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 true
2. B.Both Statement I and Statement II are false
3. C.Statement I is true but Statement II is false
4. D.Statement I is false but Statement II is true

Solution A is prepared by dissolving $1\mathrm{g}$ of a protein ($\text{molar mass}=50000\mathrm{g}\mathrm{mo}{\mathrm{l}}^{-1}$) in $0.5\mathrm{L}$ of water at $300\mathrm{K}$. Its osmotic pressure is $x\mathrm{bar}$. Solution B is made by dissolving $2\mathrm{g}$ of same protein in $1\mathrm{L}$ of water at $300\mathrm{K}$. Osmotic pressure of solution B is $y\mathrm{bar}$. Entire solution of A is mixed with entire solution of B at same temperature. The osmotic pressure of resultant solution is $z\mathrm{bar}$. $x$, $y$ and $z$ respectively are : ($R=0.083\mathrm{L}\mathrm{bar}\mathrm{mo}{\mathrm{l}}^{-1}{\mathrm{K}}^{-1}$)

1. A.$9.96\times 10^{-4}$; $9.96\times 10^{-4}$; $9.96\times 10^{-4}$
2. B.$9.96\times 10^{-4}$; $9.96\times 10^{-4}$; $19.92\times 10^{-4}$
3. C.$4.98\times 10^{-4}$; $4.98\times 10^{-4}$; $9.96\times 10^{-4}$
4. D.$4.98\times 10^{-4}$; $4.98\times 10^{-4}$; $4.98\times 10^{-4}$

Regarding the hydrides of group 15 elements $\mathrm{E}{\mathrm{H}}_3(\mathrm{E}=\mathrm{N},\mathrm{P},\mathrm{As},\mathrm{Sb})$, select the correct statement from the following : A. The stability of hydrides decreases down the group. B. The basicity of hydrides decreases down the group. C. The reducing character increases down the group. D. The boiling point increases down the group. Choose the correct answer from the options given below :

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

Given below are two statements : Statement I : The increasing order of boiling point of hydrogen halides is HCl < HBr < HI < HF. Statement II : The increasing order of melting point of hydrogen halides is HCl < HBr < HF < HI. In the light of the above statements, choose the correct answer from the options given below :

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

A solution is prepared by dissolving $0.3\mathrm{g}$ of a non-volatile non-electrolyte solute 'A' of molar mass $60\mathrm{g}\mathrm{mo}{\mathrm{l}}^{-1}$ and $0.9\mathrm{g}$ of a non-volatile non-electrolyte solute ' B ' of molar mass $180\mathrm{g}\mathrm{mo}{\mathrm{l}}^{-1}$ in $100\mathrm{mL}{\mathrm{H}}_2\mathrm{O}$ at $27^{\circ }\mathrm{C}$. Osmotic pressure of the solution will be [Given: $\mathrm{R}=0.082\mathrm{L}\mathrm{atm}{\mathrm{K}}^{-1}\mathrm{mo}{\mathrm{l}}^{-1}$ ]

1. A.$2.46\mathrm{atm}$
2. B.$0.82\mathrm{atm}$
3. C.$1.47\mathrm{atm}$
4. D.$1.23\mathrm{atm}$

' W ' g of a non-volatile electrolyte solid solute of molar mass ' M ' $\mathrm{g}\mathrm{mo}{\mathrm{l}}^{-1}$ when dissolved in $100\mathrm{mL}$ water, decreases vapour pressure of water from $640\mathrm{mm}\mathrm{Hg}$ to $600\mathrm{mm}\mathrm{Hg}$ . If aqueous solution of the electrolyte boils at $375\mathrm{K}$ and ${\mathrm{K}}_{\mathrm{b}}$ for water is $0.52\mathrm{K}\mathrm{kg}\mathrm{mo}{\mathrm{l}}^{-1}$, then the mole fraction of the electrolyte solute $(x_2)$ in the solution can be expressed as (Given : density of water = $1g/mL$ and boiling point of water = $373\mathrm{K}$ )

1. A.$\frac{16}{2.6}\times \frac{W}{M}$
2. B.$\frac{1.3}{8}\times \frac{M}{W}$
3. C.$\frac{2.6}{16}\times \frac{M}{W}$
4. D.$\frac{1.3}{8}\times \frac{W}{M}$

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

Two liquids A and B form an ideal solution. At 320 K , the vapour pressure of the solution, containing 3 mol of $A$ and 1 mol of $B$ is 500 mm Hg . At the same temperature, if 1 mol of A is further added to this solution, vapour pressure of the solution increases by 20 mm Hg . Vapour pressure (in mm Hg ) of B in pure state is _____. (Nearest integer)

Given below are two statements : Statement I : The halogen that makes longest bond with hydrogen in HX, has the smallest covalent radius in its group. Statement II : A group 15 element's hydride $\mathrm{E}{\mathrm{H}}_3$ has the lowest boiling point among corresponding hydrides of other group 15 elements. The maximum covalency of that element E is 4 . In the light of the above statements, choose the correct answer from the options given below

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

Given below are two statements : Statement I : The Henry's law constant ${\mathrm{K}}_{\mathrm{H}}$ is constant with respect to variations in solution's concentration over the range for which the solution is ideally dilute. Statement II : ${\mathrm{K}}_{\mathrm{H}}$ does not differ for the same solute in different solvents. 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 true
2. B.Statement I is true but Statement II is false
3. C.Statement I is false but Statement II is true
4. D.Both Statement I and Statement II are false

The osmotic pressure of a living cell is 12 atm at 300 K. The strength of sodium chloride solution that is isotonic with the living cell at this temperature is ____ g ${\mathrm{L}}^{-1}$. (Nearest integer) Given : R = 0.08 L atm ${\mathrm{K}}^{-1}\mathrm{mo}{\mathrm{l}}^{-1}$ Assume complete dissociation of NaCl (Given: Molar mass of Na and Cl are 23 and 35.5 g $\mathrm{mo}{\mathrm{l}}^{-1}$ respectively.)

A substance 'X' (1.5 g) dissolved in 150 g of a solvent 'Y' (molar mass = 300 g $\mathrm{mo}{\mathrm{l}}^{-1}$) led to an elevation of the boiling point by 0.5 K. The relative lowering in the vapour pressure of the solvent 'Y' is ____ $\times 10^{-2}$. (nearest integer) [Given: ${\mathrm{K}}_{\mathrm{b}}$ of the solvent = 5.0 K kg $\mathrm{mo}{\mathrm{l}}^{-1}$] Assume the solution to be dilute and no association or dissociation of X takes place in solution.

$\mathrm{HA}(aq)\rightleftharpoons {\mathrm{H}}^{+}(aq)+{\mathrm{A}}^{-}(aq)$ The freezing point depression of a $0.1\mathrm{m}$ aqueous solution of a monobasic weak acid $\mathrm{HA}$ is $0.20{}^{\circ }\mathrm{C}$. The dissociation constant for the acid is Given: $K_f({\mathrm{H}}_2\mathrm{O})=1.8\mathrm{K}\mathrm{kg}\mathrm{mo}{\mathrm{l}}^{-1}$, $\mathrm{molality}\equiv \mathrm{molarity}$

1. A.$1.90\times 10^{-3}$
2. B.$1.38\times 10^{-3}$
3. C.$1.1\times 10^{-2}$
4. D.$1.89\times 10^{-1}$

Which of the following binary mixture does not show the behaviour of minimum boiling azeotropes?

1. A.$\mathrm{C}{\mathrm{H}}_3\mathrm{OH}+\mathrm{CHC}{\mathrm{l}}_3$
2. B.${\mathrm{C}}_6{\mathrm{H}}_5\mathrm{OH}+{\mathrm{C}}_6{\mathrm{H}}_5\mathrm{N}{\mathrm{H}}_2$
3. C.${\mathrm{H}}_2\mathrm{O}+\mathrm{C}{\mathrm{H}}_3\mathrm{CO}{\mathrm{C}}_2{\mathrm{H}}_5$
4. D.$\mathrm{C}{\mathrm{S}}_2+\mathrm{C}{\mathrm{H}}_3\mathrm{COC}{\mathrm{H}}_3$

2 moles each of ethylene glycol and glucose are dissolved in 500 g of water. The boiling point of the resulting solution is: (Given : Ebullioscopic constant of water $=0.52\mathrm{K}\mathrm{kg}\mathrm{mo}{\mathrm{l}}^{-1}$ )

1. A.$377.3\mathrm{K}$
2. B.$379.2\mathrm{K}$
3. C.$375.3\mathrm{K}$
4. D.$277.3\mathrm{K}$

When $1\mathrm{g}$ each of compounds $\mathrm{AB}$ and $\mathrm{A}{\mathrm{B}}_2$ are dissolved in $15\mathrm{g}$ of water separately, they increased the boiling point of water by $2.7\mathrm{K}$ and $1.5\mathrm{K}$ respectively. The atomic mass of A (in amu) is ____ $\times 10^{-1}$ (Nearest integer) (Given : Molal boiling point elevation constant is $0.5\mathrm{K}\mathrm{kg}\mathrm{mo}{\mathrm{l}}^{-1}$ )