Question

$C{H}_{3}COOH$ dimerizes in benzene when $1.65g$ of $C{H}_{3}COOH$ dissolved in $100g$ of benzene the elevation of $Bps$ of the solution was found $0.36K$. If $K_b$ for benzene in $2.85K.kglmol$. Then find Vant Hoff factor and degree of association of $C{H}_{3}COOH$.

Answer 1

$\Delta 7_b=K_b\times \frac{W}{M\times W}\times i$

$\Rightarrow 0.36=2.85\times \frac{1.65\times 1000}{60\times 100}\times i$

$\therefore i=Va{n}^{\prime }tHofffactor=0.46$

$\underset{1-\alpha }{C{H}_{3}COOH}\rightleftharpoons \underset{\frac{\alpha }{2}}{(C{H}_{3}COOH{)}_2}$

$\therefore i=1+\frac{\alpha }{2}$

$\therefore \alpha =0.275=27.5$%= Degree of association