Question

A & B are two liquids mixed together. In solution A - B attractive forces are weaker than A-A & B-B attractive forces.

• A. The solution is an ideal solution
• B. The solutions is not an ideal solution
• C. The energy of mixing is zero
• D. Change in volume when solute and solvent mixed should be zero.

Answer 1

The correct option is B The solutions is not an ideal solution

We will revisit the definition of ideal solutions- Ideal solutions are the one which obey Raoults law.
To obey Raoult’s law, the solution should obey the following conditions.
1. Heat of mixing should be zero.
2. Change in volume when solute and solvent mixed should be zero.
As A-B attractive forces are weaker than A-A and B-B attractive forces. Energy is required to break the strong A-A, B-B bonds and to form weak A-B bonds. As energy of the mixing is not zero, the solution doesn’t obey Raoult's law.