Question

In which of the following solutions X- Y interactions are weaker than X- X or Y- Y interactions? (Where, X and Y are pure components)

• A. Bromoethane and Chloroethane
• B. Carbon disulphide and Acetone
• C. Chloroform and Acetone
• D. Nitric acid and Water
• E. Benzene and Toluene.

Hint:

Positive deviation: $\Delta H_{\text{mix}}>0$, $\Delta V_{\text{mix}}>0$. Negative deviation: $\Delta H_{\text{mix}}<0$, $\Delta V_{\text{mix}}<0$.

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
If A-B interactions are weaker than A-A and B-B, the solution shows positive deviation from Raoult's law.

Step 2: Detailed Explanation:
(A) Bromoethane + Chloroethane: Ideal or nearly ideal (similar polarity).
(B) CS2 + Acetone: CS2 is nonpolar, acetone is polar. A-B < A-A and B-B → Positive deviation.
(C) Chloroform + Acetone: H-bonding (A-B$>$A-A, B-B) → Negative deviation.
(D) HNO3 + H2O: Strong interactions → Negative deviation.
(E) Benzene + Toluene: Ideal solution.

Step 3: Final Answer:}
Weaker X-Y interactions occur for Carbon disulphide and Acetone.