The nature of charge on resulting colloidal particles when FeCl _ 3...

If ${FeCl}_{3}$ is added to hot water, a positively charged sol, hydrated ferric oxide is formed due to adsorption of ${Fe}^{3 +}$ ions.

${Fe}_{2}{O}_{3} \cdot {xH}_{2}O / {Fe}^{3 +}$

Positively charged.

Thus, When${FeCl}_{3}$​ sol is treated with hot water, it forms $Fe{( OH )}_{3}$ forming ${Fe}^{3 +}$ ions(in excess amount) and these positive ions are adsorbed preferentially.