Smoke and fog both are aerosols. In what way are they different?

Define the term $solution$. Identify the solute and solvent in the following solutions:
$(i)$ Tincture of iodine
$(ii)$ Polluted air
$(iii)$ Soda water
$(iv)$ Dilute hydrochloric acid

$(a)$ List any three differences between true solution and suspension.
$(b)$ Identify colloids from the following:
Copper sulphate solution,milk,smoke,muddy water,butter,sugar solution,face cream,lemonade

Answer the following:
$(a)$ Under which category of mixtures will you classify alloys and why?
$(b)$ $A$ solution is always a liquid. Comment.
$(c)$ Can a solution be heterogeneous?

Colloidal solution appears to be homogeneous but actually it is heterogeneous. Give justification for this statement.

The teacher instructed three students $A$,$B$ and $C$ respectively to prepare a $50\%$ (mass by volume) solution of sodium hydroxide $(NaOH)$. $A$ dissolved $50\,g$ of $NaOH$ in $100\,mL$ of water,$B$ dissolved $50\,g$ of $NaOH$ in $100\,g$ of water while $C$ dissolved $50\,g$ of $NaOH$ in water to make $100\,mL$ of solution. Which one of them has made the desired solution and why?