Question

Calculate the molality of HCl solution in a solution in which the mole fraction of water is 0.6.

Answer 1

$x_{H_{2}O}=0.6=\frac{n_{H_{2}O}}{n_{H_{2}O+n_{HCl}}}$

$⟹0.6$ $moles$ of $H_{2}O$ and $0.4$ $moles$ of $HCl$

Mass of $H_{2}O=18\times 0.6=10.8$ $gm$

$Molality=\frac{Molesofsolute}{Massofsolvent\left(kg\right)}=\frac{0.4\times 1000}{10.8}=37.037$ $molal$