A non-volatile, non-electrolyte solute $\text{'}\mathrm{X}\text{'}$ is dissolved in a suitable solvent and the osmotic pressure ($\mathrm{\pi },$ in $\mathrm{atm}$) of solutions of various concentration $\text{'}\mathrm{C}\text{'}$ in $\mathrm{g}/\mathrm{ml}$ is measured at $27 °\mathrm{C}.$ The slope of the plot $\mathrm{\pi }$ against $\text{'}\mathrm{C}\text{'}$ is found to be $5\times {10}^{-3}.$ The molecular weight of  $\text{'}\mathrm{X}\text{'}$ is: