Question

A 0.5 percent solution of potassium chloride was found to freeze at –0.24°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 1

$ΔT_f=iK_bm$
$i=\frac {(0.24×99.5×74.6)}{(1.80×0.5×1000)}=1.98$
$i=1.98$
The dissociation of potassium chloride
$α=\frac {i-1}{n-1}$
$α=\frac {0.98}{1}$
$α=0.98$
The percentage dissociation of potassium chloride $98$.

So, the answer is $98$.