The boiling point of water at $735$Torr is $99.07^{\circ}C$ . The mass of $NaCl$ added in $100\;g$ water $(K_b=0.51\;K\;kg\;mol^{-1})$ to make its boiling point $100^{\circ}C$ is

Question

$\begin{array}{1 1} 10.68\;g \\ 5.34 \;g\\ 2.67\;g \\ 26.7\;g \end{array}$