Statement 1: Glycerol is purified by distillation under reduced pressure.

Statement 2: Glycerol is a trihydric alcohol.

Both statement 1 and statement 2 are true but statement 2 is not the correct explanation of the statement 1.

Glycerol is purified by distillation under reduced pressure because it has very high B.P and decomposes at or below its B.P.