Question

the molality of Ethanol solution in which the mole fraction of water is 0.88

Answer 1

Molality is moles of solute per kg of solvent. For the given problem, the solute is ethanol and solvent is water. The mole fraction of ethanol is given as 0.88. It's simply like we have 0.88 moles of ethanol and0.12 moles of water.

Answer 2

Answer:The molality of Ethanol solution is 7.57 mol/kg.

Explanation:

Mole fraction of water,$\chi_{w}$= 0.88

Mole fraction of the ethanol ,$\chi_{e}$= 1 - 0.88 = 0.12

$\chi_{w}=\frac{n_w}{n_w+n_e}=\frac{n_w}{0.88+0.12}$

Moles of water =$n_w=0.88 mol$

Mass of water : 0.88 mole × 18 g/mol = 15.84 g = 0.01584 kg

$\chi_{e}=\frac{n_e}{n_w+n_e}=\frac{n_e}{0.88+0.12}$

Moles of ethanol =$n_e=0.12 mol$

$molality=\frac{\text{moles of ethanol}}{\text{Mass of the solvent (water)in kg}}$

$Molality=\frac{0.12 mol}{0.01584 kg}=7.57 mol/kg$

The molality of Ethanol solution is 7.57 mol/kg.