3ni2+(aq)+2co(s)⟶2co3+(aq)+3ni(s) which substance gets oxidized?

Co⁰ - 3e⁻ → Co³⁺ (cobalt loses electrons so it is oxidized)

Explanation:

When a substance is oxidized it means that it loses electrons.

When a substance is reduced it means that it gains electrons.

Ni²⁺ + 2e⁻ → Ni⁰ (nickel gains electrons so it is reduced)

Co⁰ - 3e⁻ → Co³⁺ (cobalt loses electrons so it is oxidized)

a  solution  is always transparent, light passes through with no scattering from solute particles which are molecule in size. the  solution  is homogeneous and does not settle out. a colloid is intermediate between asolution  and a  suspension. while asuspension  will separate out a colloid will not.