Answer:
Option D
Explanation:
Relationship between vant Hoff factor (i) and degree of dissociation ($\alpha$) is given by
$\alpha=\frac{1-i}{n'-1}$
where, n is the number of ions formed after dissociation .
The relationship can be obtained as follows:
For the reaction, $A\rightleftharpoons n'B$
initially 1 mole 0
after dissociation (1- $\alpha$) mole n' $\alpha$
Total number of moles present in the solution
= $(1-\alpha)+n'\alpha=1+(n'-1)\alpha$
van't Hoff factor , $i=1+(n'-1), \alpha >1 if n'\geq2$
$\therefore$ $\alpha=\frac{i-1}{n'-1}$
