Answer:
Molality = 0.216 mol.Kg⁻¹
Solution:
Molality is the amount of solute dissolved per Kg of solvent. It is expressed as,
Molality = Moles / Kg of Solvent ----- (1)
Data Given;
Mass = 11.25 g
Mass of Solvent = 325 g = 0.325 Kg
First calculate Moles for given mass as,
Moles = Mass / M.mass
Moles = 11.25 g / 159.6 g.mol⁻¹
Moles = 0.0704 mol
Now, putting value of Moles and Volume in eq. 1,
Molality = 0.0704 mol ÷ 0.325 Kg
Molality = 0.216 mol.Kg⁻¹
