Question

For an ideal solution of two components A and B which of the following is true?
(A) $\Delta {{H}_{mixing}}<0(zero)$
(B) $\Delta {{H}_{mixing}}>0(zero)$
(C) A-B interactions is stronger than A-A and B-B
(D) A-A, B-B, and A-B interactions are identical

Answer 1

Hint: A solution in which all components in all conditions of temperature and concentrations obey Raoult’s law is an ideal solution. There is no change in the properties of the ideal solution after and before mixing.

Complete step by step solution:
A solution in which all components in all conditions of temperature and concentrations obey Raoult’s law is an ideal solution. There are some conditions which satisfy the ideal solution to obey the Raoult’s law:
Their change in volume of mixing is zero, i.e., there is no change in volume when two components are mixed. $\Delta {{V}_{mixing}}=0$
Their change in enthalpy of mixing is zero, i.e., there is no change in heat when two components are mixed. $\Delta {{H}_{mixing}}=0$
So, from this, we can say that in an ideal solution there is no change in volume and enthalpy even when the solute and solvent are mixed in any proportion.
At the molecular level, when A and B are mixed there are three interactions i.e., A-A, B-B, and A-B. Where A-A and B-B are the interaction of solute and solvent, and A-B is the interaction of solution. It was found that all three interactions remain the same throughout the process. So, all the interactions are the same or identical.

Therefore, the correct answer is an option (D) A-A, B-B, and A-B interactions are identical.

Note: Coming to practical application, there is no solution which is ideal. But some of the examples that are considered as an ideal solution are a mixture of benzene and toluene, a mixture of ethyl bromide and ethyl chloride, etc.