Liquid Solution JEE Main | Boiling Point Elevation PYQ

JEE MAIN 2025

29-01-2025 SHIFT-1

Question

1.24 g of ${\rm{A}}{{\rm{X}}_2}$ (molar mass $124\;{\rm{g}}\;{\rm{mo}}{{\rm{l}}^{ - 1}}$) is dissolved in 1 kg of water to form a solution with boiling point of ${100.0156^\circ }{\rm{C}}$, whill $25.4\;{{\rm{g}}^2}$ of ${\rm{A}}{{\rm{Y}}_2}$ (molar mass $250\;{\rm{g}}\;{\rm{mo}}{{\rm{l}}^{ - 1}}$) in 2 kg of water constitutes a solution with a boiling point of ${100.0260^\circ }{\rm{C}}$.
${{\rm{K}}_{\rm{b}}}\left( {{{\rm{H}}_2}{\rm{O}}} \right) = 0.52\;{\rm{K}}\;{\rm{kg}}\;{\rm{mo}}{{\rm{l}}^{ - 1}}$
Which of the following is correct?

Select the correct option:

${\rm{A}}{{\rm{X}}_2}$ and ${\rm{A}}{{\rm{Y}}_2}$ (both) are completely unionised

${\rm{A}}{{\rm{X}}_2}$ and ${\rm{A}}{{\rm{Y}}_2}$ (both) are fully ionised.

${\rm{A}}{{\rm{X}}_2}$ is completely unionised while ${\rm{A}}{{\rm{Y}}_2}$ is fully ionised.

${\rm{A}}{{\rm{X}}_2}$ is fully ionised while ${\rm{A}}{{\rm{Y}}_2}$ is completely unionised.

✓ Correct! Well done.

✗ Incorrect. Try again or view the solution.

Solution