Target Exam

CUET

Subject

Chemistry

Chapter

Physical: Solutions

Question:

Which of the following statements is/ are correct?

(A) For an ideal solution, the enthalpy and volume of mixing of pure components are zero.
(B) The inter-molecular attractive forces between A-A and B-B are greater than those between A-B for an ideal binary solution.
(C) The inter-molecular attractive forces between A-A and B-B are of the same order as those between A-B for an ideal binary solution
(D) For an ideal solution, the enthalpy and volume of mixing of pure components to form the solution are positive.

Choose the correct answer from the options given below:

Options:

(C) and (D) only

(A), (B) and (D) only

(A) and (C) only

(B), (C) and (D) only

Correct Answer:

(A) and (C) only

Explanation:

The correct answer is Option (3) → (A) and (C) only

(A) For an ideal solution, the enthalpy and volume of mixing of pure components are zero: This is correct. In an ideal solution, the total volume is simply the sum of the volumes of the individual components ($\Delta V_{mix} = 0$), and no heat is absorbed or released during the mixing process ($\Delta H_{mix} = 0$).

(B) The inter-molecular attractive forces between A-A and B-B are greater than those between A-B...: This is incorrect. This condition describes a non-ideal solution with a positive deviation from Raoult's law (like ethanol and cyclohexane), where the components prefer their own company over mixing.

(C) The inter-molecular attractive forces between A-A and B-B are of the same order as those between A-B...: This is correct. This is the fundamental molecular requirement for an ideal solution. Because the $A-B$ interactions are essentially identical to the $A-A$ and $B-B$ interactions, there is no net energy change upon mixing.

(D) For an ideal solution, the enthalpy and volume of mixing... are positive: This is incorrect. As stated in (A), these values must be zero. Positive values indicate a non-ideal solution with positive deviation.