Question

It is fine to say that "colloids are heterogeneous systems"

But is this statement correct " colloids are a heterogeneous system in which phase boundaries exist. "

If its correct then how? Provide with an example.

Answer 1

Colloids are heterogeneous system. But there won't be a degidefi line of boundaries between the phases. The phases means different type of particles. In colloids the different particles are mixed together (but still those particles exist as such). So as you said colloids are heterogeneous system but there won't be a phase difference between the phases, the phases will be mixed together.