Question

Which one of the following binary liquid mixture exhibit positive deviation from Raoult's law ?

• A. Carbon disulphide-acetone
• B. Chloroform-acetone
• C. Bromobenzene-chlrobenzene
• D. Benzene-toluene
• E. Phenol-aniline

Answer 1

The correct option is A Carbon disulphide-acetone

Positive Deviation from Raoult's Law occurs when the vapour pressure of the component is greater than what is expected in Raoult's Law.

When carbon disulphide is added to the acetone, this weakens the dipolar interaction between a molecule of solute-solvent (A – B) than the respective interaction between solute-solute (A – B) and solvent – solvent (B – B), which leads to increase in vapour pressure. And the mixture shows a positive deviation in vapour pressure than Raoult’s Law.

Carbon disulphide acetone $(C{S}_2-C{H}_{3}COC{H}_3)$ mixture shows positive deviation from Raoult's law.

Hence, option A is correct.