A solution of sodium sulphate contains 92   g of Na + ions per kilogram of water. The molality of Na +…

Moles of $N{a}^{+}=\frac{\mathrm{W}\mathrm{e}\mathrm{i}\mathrm{g}\mathrm{h}\mathrm{t}\mathrm{ }\mathrm{o}\mathrm{f}\mathrm{ }\mathrm{N}{\mathrm{a}}^{+}\mathrm{ }\mathrm{i}\mathrm{o}\mathrm{n}\mathrm{s}}{\mathrm{M}\mathrm{o}\mathrm{l}\mathrm{e}\mathrm{c}\mathrm{u}\mathrm{l}\mathrm{a}\mathrm{r}\mathrm{ }\mathrm{w}\mathrm{e}\mathrm{i}\mathrm{g}\mathrm{h}\mathrm{t}}=\frac{92}{23}=4$
 

Molality is number of moles of solute present per Kg of Solvent

4 mole of $N{a}^{+}$ are present in 1 kg of water Hence, molality of $N{a}^{+}$ ions will be 4