Question

A binary liquid mixture is formed by mixing ethanol and acetone. Which of the following statement is correct regarding the behaviour of the solution ?

• A. The solution is non-ideal, showing negative deviation from Raoult's Law.
• B. The solution is ideal, obeying Raoult's Law.
• C. The solution is non-ideal, showing positive deviation from Raoult's Law.
• D. It can either show positive deviation or negative deviation from Raoult's Law.

Answer 1

The correct option is C The solution is non-ideal, showing positive deviation from Raoult's Law.

Positive deviation:
Solvent-solute interaction is less than the solvent-solvent and the solute-solute interactions
Negative deviation:
Solvent-solute interaction is more than the solvent-solvent and the solute-solute interactions.

Molecules of ethanol n pure state are hydrogen bonded but when acetone and ethanol are mixed together, intermolecular attractive forces are weakened by the breaking of some hydrogen bonds. Thus acetone-ethanol interaction is weaker as comapred to ethanol-ethanol and acetone-acetone interactions.
Positive deviation is there.
Option (c) is correct.