Statement I: When a solution of non-volatile solute in water is cooled slightly below its freezing temperature, some ice separates out and then freezing stops.
Statement II: Separation of ice increases the molality of the left over solution.

When a solution of non-volatile solute in water is cooled slightly below its freezing temperature,

Ice separates out and then freezing stops ..... true

Below FP of any liquid, freezing is always a spontaneous process and the excess solvent separates out as a solid

(I) is true

The left over solution contains relatively lesser solvent , its concentration (molality) increases

(II) is true