If the degree of association is 70% for the reaction $2 \mathrm{A}\rightleftharpoons (\mathrm{A}{)}_2$ athe van’t Hoff factor for the solute ‘A’ is

Given data:It is given to identify van'tHoff factor of solute A.

Explanation:

$$\begin{gathered} 2A\rightleftharpoons \left(A{)}_2\text{ van't Hoff factor }\right(i) \\ 70\%=0.7\text{ per unit, i.e. } \\ \alpha =0.70\text{ (Given), } \\ \text{ where, }\alpha =\text{ degree of association } \\ n= a number of units are undergoing association \\ \begin{array}{l}i=(1-\alpha )+\frac{\alpha }{n}\\ \Rightarrow (1-0.70)+\frac{0.70}{2}\\ i=0.30+0.35\Rightarrow 0.65\end{array} \end{gathered}$$

Hence, the correct option is: (D)