The sol given below with

$\mathrm{FeCl}_{3}$ added to hot water

$\mathrm{KI}$ added to $\mathrm{AgNO}_{3}$ solution

$\mathrm{AgNO}_{3}$ added to $\mathrm{KI}$ solution

$\mathrm{Al}_{2} \mathrm{O}_{3} \cdot \mathrm{xH}_{2} \mathrm{O}$ in water