Chemistry - Concentration Terms Question with Solution | TestHub

Formula unit mass of sodium chloride = $23 + 35.5 {\mathrm{gmol}}^{-1} = 58.5 {\mathrm{gmol}}^{-1}$
$\therefore \mathrm{m}\left(\mathrm{molality}\right)=\frac{1000\times \mathrm{M}}{1000\times \mathrm{d}-\mathrm{M}\times \mathrm{M}.\mathrm{W}\text{ of solute }}$   ...$(\mathrm{M} = \mathrm{Molarity} \mathrm{of} \mathrm{solution})$

$=\frac{1000\times 3}{1000\times 1-(3\times 58.5)}=3.64$

$=364\times {10}^{-2}$