A 0.5 percent solution of potassium chloride was found to freeze at $-$0.24$^\circ$C. The percentage dissociation of potassium chloride is ______________. (Nearest integer)
(Molal depression constant for water is 1.80 K kg mol$-$1 and molar mass of KCl is 74.6 g mol$-$1)
Answer (integer)
98
Solution
$\Delta \mathrm{T}_{\mathrm{f}}=\mathrm{iK}_{\mathrm{b}} \mathrm{m}$
<br/><br/>
$$
\begin{aligned}
&\mathrm{i}=\frac{0.24 \times 99.5 \times 74.6}{1.80 \times 0.5 \times 1000} \\\\
&=1.98 \\\\
&\alpha=\frac{\mathrm{i}-1}{\mathrm{n}-1}=\frac{0.98}{1}=0.98 = 98 \,\%
\end{aligned}
$$
About this question
Subject: Chemistry · Chapter: States of Matter · Topic: Gas Laws
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