Solutions · JEE Main previous year questions

2024 14 questions

1. Q902024 · 9 Apr 2024 · Shift 2· Numerical answer

   The vapor pressure of pure benzene and methyl benzene at $27^{\circ }\mathrm{C}$ is given as $80\mathrm{Torr}$ and $24\mathrm{Torr}$, respectively. The mole fraction of methyl benzene in vapor phase, in equilibrium with an equimolar mixture of those two liquids (ideal solution) at the same temperature is ____ $\times 10^{-2}$ (nearest integer)

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   Answer: 23

2. Q862024 · 8 Apr 2024 · Shift 1· Numerical answer

   A solution containing $10\mathrm{g}$ of an electrolyte $\mathrm{A}{\mathrm{B}}_2$ in $100\mathrm{g}$ of water boils at $100.52^{\circ }\mathrm{C}$. The degree of ionization of the electrolyte $(\alpha )$ is ____ $\times 10^{-1}$. (nearest integer) $[\text{Given : Molar mass of }\mathrm{A}{\mathrm{B}}_2=200\mathrm{g}\mathrm{mo}{\mathrm{l}}^{-1}\text{, }{\mathrm{K}}_{\mathrm{b}}\text{ (molal boiling point elevation const. of water)}=0.52\mathrm{K}\mathrm{kg}\mathrm{mo}{\mathrm{l}}^{-1}\text{, boiling point of water}=100^{\circ }\mathrm{C}\text{; }\mathrm{A}{\mathrm{B}}_2\text{ ionises as }\mathrm{A}{\mathrm{B}}_2\to {\mathrm{A}}^{2+}+2{\mathrm{B}}^{-}]$

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   Answer: 5

3. Q842024 · 6 Apr 2024 · Shift 2· Numerical answer
   
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   Answer: 543

4. Q812024 · 4 Apr 2024 · Shift 1· Numerical answer

   $2.5\mathrm{g}$ of a non-volatile, non-electrolyte is dissolved in $100\mathrm{g}$ of water at $25^{\circ }\mathrm{C}$. The solution showed a boiling point elevation by $2^{\circ }\mathrm{C}$. Assuming the solute concentration is negligible with respect to the solvent concentration, the vapor pressure of the resulting aqueous solution is ____ $\mathrm{mm}\mathrm{of}\mathrm{Hg}$ (nearest integer) [Given : Molal boiling point elevation constant of water $({\mathrm{K}}_{\mathrm{b}})=0.52K.\mathrm{kgmo}{\mathrm{l}}^{-1}$, $1\mathrm{atm}$ pressure $=760\mathrm{mm}\mathrm{of}\mathrm{Hg}$, molar mass of water $=18\mathrm{g}\mathrm{mo}{\mathrm{l}}^{-1}$]

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   Answer: 707

5. Q852024 · 4 Apr 2024 · Shift 2· Numerical answer

   $2.7\text{ kg}$ of each of water and acetic acid are mixed. The freezing point of the solution will be $-x^{\circ }\text{C}$. Consider the acetic acid does not dimerise in water, nor dissociates in water. $x=$ ________ (nearest integer) [Given: Molar mass of water $=18{\text{ g mol}}^{-1}$, acetic acid $=60{\text{ g mol}}^{-1}$ ${\text{K}}_{\text{f}}{\text{H}}_2\text{O}:1.86{\text{ K kg mol}}^{-1}$ ${\text{K}}_{\text{f}}\text{ acetic acid}:3.90{\text{ K kg mol}}^{-1}$ freezing point: ${\text{H}}_2\text{O}=273\text{ K}$, acetic acid $=290\text{ K}$]

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   Answer: 31

6. Q712024 · 1 Feb 2024 · Shift 1

   We have three aqueous solutions of $\mathrm{NaCl}$ labelled as ' $\mathrm{A}$ ', ' $\mathrm{B}$ ' and ' $\mathrm{C}$ ' with concentration $0.1\mathrm{M}$, $0.01\mathrm{M}$ and $0.001\mathrm{M}$, respectively. The value of van 't Hoff factor(i) for these solutions will be in the order :

   1. A.${\mathrm{i}}_{\mathrm{A}}<{\mathrm{i}}_{\mathrm{C}}<{\mathrm{i}}_{\mathrm{B}}$
   2. B.${\mathrm{i}}_{\mathrm{A}}<{\mathrm{i}}_{\mathrm{B}}<{\mathrm{i}}_{\mathrm{C}}$
   3. C.${\mathrm{i}}_{\mathrm{A}}>{\mathrm{i}}_{\mathrm{B}}>{\mathrm{i}}_{\mathrm{C}}$
   4. D.${\mathrm{i}}_{\mathrm{A}}={\mathrm{i}}_{\mathrm{B}}={\mathrm{i}}_{\mathrm{C}}$
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   Answer: B

7. Q742024 · 1 Feb 2024 · Shift 1

   Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A): $\mathrm{P}{\mathrm{H}}_3$ has lower boiling point than $\mathrm{N}{\mathrm{H}}_3$. Reason (R) : In liquid state $\mathrm{N}{\mathrm{H}}_3$ molecules are associated through van der Waals forces, but $\mathrm{P}{\mathrm{H}}_3$ molecules are associated through hydrogen bonding. In the light of the above statements, choose the most appropriate answer from the options given below :

   1. A.Both (A) and (R) are correct and (R) is the correct explanation of (A)
   2. B.(A) is not correct but (R) is correct
   3. C.(A) is correct but (R) is not correct
   4. D.Both $(\mathbf{A})$ and $(\mathbf{R})$ are correct but $(\mathbf{R})$ is not the correct explanation of $(\mathbf{A})$
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   Answer: C

8. Q762024 · 1 Feb 2024 · Shift 2

   Which among the followng has highest boiling point?

   1. A.$\mathrm{C}{\mathrm{H}}_3\mathrm{C}{\mathrm{H}}_2\mathrm{C}{\mathrm{H}}_2\mathrm{C}{\mathrm{H}}_2-\mathrm{OH}$
   2. B.$\mathrm{C}{\mathrm{H}}_3\mathrm{C}{\mathrm{H}}_2\mathrm{C}{\mathrm{H}}_2\mathrm{C}{\mathrm{H}}_3$
   3. C.$\mathrm{C}{\mathrm{H}}_3\mathrm{C}{\mathrm{H}}_2\mathrm{C}{\mathrm{H}}_2\mathrm{CHO}$
   4. D.${\mathrm{H}}_5{\mathrm{C}}_2-\mathrm{O}-{\mathrm{C}}_2{\mathrm{H}}_5$
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   Answer: A

9. Q822024 · 1 Feb 2024 · Shift 2· Numerical answer

   Mass of ethylene glycol (antifreeze) to be added to $18.6\text{ kg}$ of water to protect the freezing point at $-24^{\circ }\text{C}$ is ________ $\text{kg}$ (Molar mass in $\mathrm{g}\mathrm{mo}{\mathrm{l}}^{-1}$ for ethylene glycol $62$, ${\mathrm{K}}_f$ of water $=1.86{\text{ K kg mol}}^{-1}$ )

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   Answer: 15

10. Q642024 · 31 Jan 2024 · Shift 1

    Given below are two statements: Statement - I: Noble gases have very high boiling points. Statement - II: Noble gases are monoatomic gases. They are held together by strong dispersion forces. Because of this they are liquefied at very low temperature. Hence, they have very high boiling points. 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.Statement I is false but Statement II is true.
    4. D.Both Statement I and Statement II are true.
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    Answer: A

11. Q662024 · 31 Jan 2024 · Shift 1

    Identify the mixture that shows positive deviations from Raoult's Law

    1. A.$(\mathrm{C}{\mathrm{H}}_3{)}_2\mathrm{CO}+\mathrm{C}{\mathrm{S}}_2$
    2. B.$(\mathrm{C}{\mathrm{H}}_3{)}_2\mathrm{CO}+{\mathrm{C}}_6{\mathrm{H}}_5\mathrm{N}{\mathrm{H}}_2$
    3. C.$\mathrm{CHC}{\mathrm{l}}_3+{\mathrm{C}}_6{\mathrm{H}}_6$
    4. D.$\mathrm{CHC}{\mathrm{l}}_3+(\mathrm{C}{\mathrm{H}}_3{)}_2\mathrm{CO}$
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    Answer: A

12. Q682024 · 30 Jan 2024 · Shift 1

    What happens to freezing point of benzene when small quantity of napthalene is added to benzene?

    1. A.Increases
    2. B.Decreases
    3. C.Remains unchanged
    4. D.First decreases and then increases
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    Answer: B

13. Q902024 · 29 Jan 2024 · Shift 1· Numerical answer

    The osmotic pressure of a dilute solution is $7\times 10^5\text{ Pa}$ at $273\text{ K}$. Osmotic pressure of the same solution at $283\text{ K}$ is _________ $\times 10^4\mathrm{N}{\mathrm{m}}^{-2}$.

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    Answer: 73

14. Q672024 · 27 Jan 2024 · Shift 1

    A solution of two miscible liquids showing negative deviation from Raoult's law will have :

    1. A.increased vapour pressure, increased boiling point
    2. B.increased vapour pressure, decreased boiling point
    3. C.decreased vapour pressure, decreased boiling point
    4. D.decreased vapour pressure, increased boiling point
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    Answer: D