is negative and positive deviation only seen in case of non ideal solution ?

Non-ideal solutions exhibit either positive or negative deviations from Raoult’s law.

Only a few binary solutions strictly obey Raoult's law over the whole range of concentrations. In many cases, mixtures of two miscible liquids form non-ideal solutions over most of the concentration range and the system exhibit either a positive or negative deviation from Raoult's law. These deviations from Raoult's law are generally observed for systems in which the two components A and B of the liquid mixture have different molecular structure.