Question

A compound `H_(2)X` with molar mass of `80 g` is dissolved in a solvent having density of `0.4 g mL^(-1)`. Assuming no change in volume upon dissolution, the molality of a `3.2` molar solution is

Answer 1

Correct Answer - 8
Volume of solvent = Volume of solution
Mass of one litre solvent `=1000 xx 0.4 = 400g` or 0.4 kg
Molality `= ("Number of moles of solute")/("Mass of solvent in kg")=(3.2)/(0.4)=8`]