For an ideal solution, which of the following is true? 

CONCEPT:

Ideal Solution

• An ideal solution is defined as a solution that obeys Raoult's law over the entire range of concentration.
• In an ideal solution, the intermolecular interactions between the solute and solvent molecules are similar to those between the solute molecules and the solvent molecules.
• For an ideal solution, the mixing process is thermodynamically ideal, meaning:
  • The enthalpy of mixing (ΔH_mix) is zero.
  • The volume of mixing (ΔV_mix) is zero.
  • The entropy of mixing (ΔS_mix) is positive due to increased randomness.
  • The Gibbs free energy of mixing (ΔG_mix) is negative for spontaneous mixing.

EXPLANATION:

• For an ideal solution:
  • ΔH_mix = 0 because there is no heat exchange during mixing.
  • ΔV_mix = 0 because the total volume remains unchanged during mixing.
  • ΔG_mix ≠ 0 because the mixing process is spontaneous, making the Gibbs free energy negative.
  • ΔS_mix ≠ 0 because entropy increases due to mixing.
• From the options provided:
  • Option 1: ΔH_mix ≠ 0 is incorrect because, for an ideal solution, ΔH_mix = 0.
  • Option 2: ΔV_mix = 0 is correct because the volume of mixing is zero for an ideal solution.
  • Option 3: ΔG_mix = 0 is incorrect because ΔG_mix is negative for an ideal solution.
  • Option 4: ΔS_mix = 0 is incorrect because ΔS_mix is positive for an ideal solution.

Therefore, the correct answer is Option 2: ΔV_mix = 0.