d
The concept of an ideal solution is fundamental to chemical thermodynamics and its applications, such as the use of colligative properties. An ideal solution or ideal mixture is a solution in which the enthalpy of solution \(\left(\Delta H _{\text {solution }}= O \right)\) is zero. As the enthalpy of the solution nears zero, the solution becomes more ideal.

Since the enthalpy of mixing (solution) is zero, the change in Gibbs energy on mixing is determined solely by the entropy of mixing ( \(\Delta S _{\text {solution }}\) ).

So the \(\Delta G\) is not zero.