Question

Given below are two statements: Statement (I): 1,2,3–Trihydroxypropane can be separated from water by simple distillation. Statement (II): An azeotropic mixture cannot be separated by fractional distillation. In the light of the above statements, choose the correct answer from the options given below:

• A. Both Statement I and Statement II are true
• B. Both Statement I and Statement II are false
• C. Statement I is true but Statement II is false
• D. Statement I is false but Statement II is true

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
Separation techniques depend on physical properties like boiling point. Simple distillation is used when boiling points differ significantly and the substance is stable. Fractional distillation is used for closer boiling points but fails for constant-boiling mixtures.
Step 2: Detailed Explanation:
Analysis of Statement (I):
1,2,3-Trihydroxypropane (glycerol) has a very high boiling point (\(290^{\circ}C\)) and it tends to decompose at or near its boiling point.
Separating it from water via simple distillation at atmospheric pressure is difficult and causes product loss. Instead, it is separated by distillation under reduced pressure (vacuum distillation), which lowers the boiling point below the decomposition temperature.
Therefore, Statement (I) is False.

Analysis of Statement (II):
An azeotropic mixture is a constant-boiling mixture where the composition of the vapor phase is identical to that of the liquid phase.
Because the concentrations are the same, fractional distillation cannot change the purity beyond the azeotropic point (e.g., 95% ethanol).
Therefore, Statement (II) is True.
Step 3: Final Answer:
Statement I is false but Statement II is true.