Question

The density of $3 M$ solution of $NaCl$ is $1.0 \,g \,mL^{ -1}$. Molality of the solution is _______ $\times 10^{-2} m$. (Nearest integer).
Given: Molar mass of $Na$ and $Cl$ is $23$ and $35.5 \,g \,mol ^{-1}$ respectively.

Answer 1

$ m =\frac{1000 \times M }{1000 \times d - M \times M . W \text { of solute }}$
$ =\frac{1000 \times 3}{1000 \times 1-(3 \times 58.5)}=3.64 $
$ =364 \times 10^{-2}$