The sol given below with negatively charged colloidal particles is:

$\left(1\right){FeCl}_{3}$ added to hot water,

$( 2 )$ When ${AgNO}_{3}$ is added to $KI$,

$( 3 )$ When $Kl$ is added to ${AgNO}_{3}$,

$\left(4\right){Al}_{2}{O}_{3} \cdot 2{H}_{2}O$ in water

$Al{\left(OH\right)}_{3} / {Al}^{3 +}$ positively charged