JEE PYQ: Solutions And Colligative Properties Question 12
Question 12 - 2021 (26 Feb Shift 2)
When 12.2 g of benzoic acid is dissolved in 100 g of water, the freezing point of solution was found to be $-0.93°C$. [$K_f(\text{H}_2\text{O}) = 1.86$ K kg mol$^{-1}$]. The number (n) of benzoic acid molecules associated (assuming 100% association) is:
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Answer: 2
Solution
$n$ PhCOOH $\rightarrow$ (PhCOOH)$_n$. $0.93 = \frac{1}{n} \times 1.86 \times \frac{12.2}{122 \times 0.1}$. $n = 2$.
BETA
