JEE Main 2025 — Solutions Question with Solution
JEE Main 2025 (29 Jan Shift 1)
Question
1.24 g of (molar mass ) is dissolved in 1 kg of water to form a solution with boiling point of , while of (molar mass ) in 2 kg of water constitutes a solution with a boiling point of .
Which of the following is correct ?
Choose an option
Show full solutionCorrect option: A
Correct answer
A is fully ionised while is completely unionised.
Step-by-step explanation
For
$\begin{aligned}
& \Delta \mathrm{T}_{\mathrm{b}}=\mathrm{i} \mathrm{~K} \mathrm{~m} \\
& 0.0156=\mathrm{i} \times 0.52 \times \frac{1.24}{124 \times 1} \\
& 3=\mathrm{i} \\
& 3=1+2 \alpha \\
& 1=\alpha
\end{aligned}$
For
$\begin{aligned}
& \Delta \mathrm{T}_{\mathrm{b}}=\mathrm{i} \mathrm{~K}_{\mathrm{b}} \mathrm{~m} \\
& 0.0260=\mathrm{i} \times 0.52 \times \frac{25.4}{250 \times 2} \\
& \mathrm{i} \approx 1
\end{aligned}$
is completely ionised is completely unionised
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