The vapour pressure of a solution having 2.0g of a solute X(molar mass $32gmol^{-1}$) in 100g of $CS_2$ (vapour pressure 854 Torr) is 848.9 Torr.The molecular formula of the solute is

Question

$\begin{array}{1 1}X\\X_2\\X_4\\X_8\end{array}$