The molal elevation constant of water is 0.51. The boiling point of 0.1 molal aqueous NaCI solution is nearly:

$$\begin{gathered} {\mathrm{\Delta T}}_{\mathrm{b}}={\mathrm{iK}}_{\mathrm{b}}\times \mathrm{m} \\ \text{G.m.wt of }\mathrm{NaCl}=58.5\mathrm{g} \\ \text{molality }\left(\mathrm{m}\right)=0.1\mathrm{molal} \end{gathered}$$
For NaCI, Van't Hoff factor (i)=2 

Boiling point $\left({\mathrm{T}}_{\mathrm{s}}\right)$
$$\begin{gathered} =2\times 0.5\times 0.1=0.1\therefore \text{ B.P of solution }=100+{\mathrm{\Delta T}}_{\mathrm{b}}=100{.1}^{\circ }\mathrm{C} \\ {100}^{\circ }\mathrm{C}\text{ is B.P of pure }{\mathrm{H}}_2\mathrm{O} \end{gathered}$$