$A_3{B}_2$ is a sparingly soluble salt of molar mass M($gmo{l}^{-1}$) and solubility x $g{L}^{-1}$. The solubility product satisfies $K_{sp} = a {\left(\frac{x}{M}\right)}^5$ . The value of a is.....

$$\begin{gathered} A_3{B}_2 \leftrightarrow 2A^{2+} + 2 B^{3-} \\ 3S 2S \\ {K}_{Sp }= {\left(3s\right)}^3{\left(2s\right)}^2{K}_{sp }= 108S^{5 } and s ={\left(\frac{x}{m}\right)}^5 \\ {K}_{sp }=108 {\left(\frac{x}{m}\right)}^5 \\ So. K_{sp }=a{\left(\frac{x}{m}\right)}^5 \\ a = 108 \end{gathered}$$

Hence, the correct answer is 108.