The correct option is All three
Explanation
Colloids are heterogeneous mixtures consisting of two phases: the dispersed phase (the substance distributed) and the dispersion medium (the substance in which the phase is suspended). The classification of colloids depends on the physical state (Gas, Liquid, or Solid) of these two components.
Statement-wise Analysis:
- Pair 1: Correct.
Smoke is a type of colloid known as a Solid Aerosol. It consists of solid particles (dispersed phase) suspended in a gas (dispersion medium). Therefore, the dispersing medium is Gas. - Pair 2: Correct.
Shaving cream is a type of colloid known as a Foam. It consists of gas bubbles (dispersed phase) trapped within a liquid (dispersion medium). Therefore, the dispersing medium is Liquid. - Pair 3: Correct.
Jelly is a type of colloid known as a Gel. It consists of liquid droplets (dispersed phase) trapped within a solid network (dispersion medium). Therefore, the dispersing medium is Solid.
Key Takeaway:
The physical state of the dispersion medium defines the continuous phase of the colloid: Gas (Aerosols), Liquid (Sols, Emulsions, Foams), or Solid (Solid Sols, Gels).