What happens when a lyophilic sol is added to a lyophobic sol?

When a lyophilic sol (solvent-loving colloid) is added to a lyophobic sol (solvent-hating colloid), the lyophilic sol particles form a protective layer (film) around the lyophobic sol particles.

This process is called protective action of lyophilic colloids. The lyophilic colloid gets adsorbed on the surface of lyophobic colloid particles, forming a protective film. This prevents the coagulation of the lyophobic sol and makes it more stable.

The answer is Option 1: Film of lyophilic sol is formed over lyophobic sol.