Solutions · JEE Main previous year questions

2025 10 questions

1. Q562025 · 8 Apr 2025 · Shift 2

   $\mathrm{HA}(aq)\rightleftharpoons {\mathrm{H}}^{+}(aq)+{\mathrm{A}}^{-}(aq)$ 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.$1.89\times 10^{-1}$
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   Answer: B

2. Q612025 · 8 Apr 2025 · Shift 2

   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.$\mathrm{C}{\mathrm{S}}_2+\mathrm{C}{\mathrm{H}}_3\mathrm{COC}{\mathrm{H}}_3$
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   Answer: B

3. Q602025 · 3 Apr 2025 · Shift 1

   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.$277.3\mathrm{K}$
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   Answer: A

4. Q722025 · 2 Apr 2025 · Shift 2· Numerical answer

   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 $0.5\mathrm{K}\mathrm{kg}\mathrm{mo}{\mathrm{l}}^{-1}$ )

   Show answer

   Answer: 25

5. Q532025 · 29 Jan 2025 · Shift 2

   Given below are two statements : Statement (I): NaCl is added to the ice at 0°C, present in the ice cream box to prevent the melting of ice cream. Statement (II): On addition of NaCl to ice at 0°C, there is a depression in freezing point. 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 but 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
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   Answer: C

6. Q522025 · 28 Jan 2025 · Shift 1

   What is the freezing point depression constant of a solvent, $50\mathrm{g}$ of which contain $1\mathrm{g}$ non volatile solute (molar mass $256\mathrm{g}\mathrm{mo}{\mathrm{l}}^{-1}$) and the decrease in freezing point is $0.40\mathrm{K}$?

   1. A.$4.43\mathrm{K}\mathrm{kg}\mathrm{mo}{\mathrm{l}}^{-1}$
   2. B.$3.72\mathrm{K}\mathrm{kg}\mathrm{mo}{\mathrm{l}}^{-1}$
   3. C.$5.12\mathrm{K}\mathrm{kg}\mathrm{mo}{\mathrm{l}}^{-1}$
   4. D.$1.86\mathrm{K}\mathrm{kg}\mathrm{mo}{\mathrm{l}}^{-1}$
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   Answer: C

7. Q522025 · 24 Jan 2025 · Shift 1

   The large difference between the melting and boiling points of oxygen and sulphur may be explained on the basis of

   1. A.Atomicity
   2. B.Electron gain enthalpy
   3. C.Atomic size
   4. D.Electronegativity
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   Answer: A

8. Q542025 · 24 Jan 2025 · Shift 1
   
   1. A.
   2. B.
   3. C.
   4. D.
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   Answer: C

9. Q642025 · 24 Jan 2025 · Shift 1

   Let us consider an endothermic reaction which is non-spontaneous at the freezing point of water. However, the reaction is spontaneous at boiling point of water. Choose the correct option.

   1. A.Both $\Delta \mathrm{H}$ and $\Delta \mathrm{S}$ are (-ve)
   2. B.$\Delta \mathrm{H}$ is (+ve) but $\Delta \mathrm{S}$ is (-ve)
   3. C.$\Delta \mathrm{H}$ is (-ve) but $\Delta \mathrm{S}$ is (+ve)
   4. D.Both $\Delta \mathrm{H}$ and $\Delta \mathrm{S}$ are (+ve)
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   Answer: D

10. Q652025 · 22 Jan 2025 · Shift 1

    Arrange the following solutions in order of their increasing boiling points. (i) $10^{-4}\mathrm{M}\mathrm{NaCl}$ (ii) $10^{-4}\mathrm{M}$ Urea (iii) $10^{-3}\mathrm{M}\mathrm{NaCl}$ (iv) $10^{-2}\mathrm{M}\mathrm{NaCl}$

    1. A.(i) < (ii) < (iii) < (iv)
    2. B.(ii) < (i) < (iii) < (iv)
    3. C.(iv) < (iii) < (i) < (ii)
    4. D.(ii) < (i) $\equiv$ (iii) < (iv)
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    Answer: B