Which of the following is true about ideal solutions?

The correct answer is Option (3) → Both (1) and (2)

An ideal solution obeys Raoult’s law over the entire range of concentration. Its A–B attractions are nearly equal to the A–A and B–B attractions, so mixing changes neither the energy nor the packing of the molecules: Δ_mixH = 0 and Δ_mixV = 0. Both statements are true, so the complete answer is Option (3).

NCERT (2026-27 edition):
1.5.1 Ideal Solutions – “… The ideal solutions have two other important properties. The enthalpy of mixing of the pure components to form the solution is zero and the volume of mixing is also zero, i.e.,

    \( \displaystyle \Delta_{\text{mix}}H=0,\qquad \Delta_{\text{mix}}V=0 \qquad (1.21) \)”