$\begin{array}{1 1}(a)\;\text{The solution is non-ideal,showing +ve deviation from Raoult's law}\\(b)\;\text{The solution is non-ideal,showing -ve deviation from Raoult's law}\\(c)\;\text{n-heptane shows +ve deviation while ethanol shows -ve deviation from Raoult's law}\\(d)\;\text{The solution formed is an ideal solution}\end{array}$
