Question

A compound `H_(2)X` with molar weight of 80 g is dissolved in a solvent having density of `0.4 g ml^(-1)`. Assumingno change in volume upon dissolution, the molality of a 3.2 molar solution is

Answer 1

Correct Answer - 8
Given 3.2 M solution
`therefore` moles of solute = 3.2 mol
Consider 1 L Solution.
`therefore` volume of solvent = 1 L
`P_("solvent")=0.4 g.mL^(-1) therefore m_("solvent")=P xx V=400 g`
`therefore` molality `=(3.2 mol)/(0.4 kg)= 8` molal.