In a mixture component $A$ and component $B$ Shows negative Deviation as, $\Delta V _{\text {mixing }}\,<\,0$

i.e. For Negative Deviation, $\Delta V _{\text {mixing }}= O , \Delta H _{\text {mixing }}=- ve$

Because, the forces of attraction between components $A$ and $B$ is greater.

Due to that the tendency of escaping of molecules $AB$ from solution becomes less than that of pure liquids.

$A – B$ attractive forces is greater than $A – A$ and $B – B$ attractive forces.