Why is ferric hydroxide colloid positively charged when prepared by adding ferric chloride to hot water?

Question

Why is ferric hydroxide colloid positively charged when prepared by adding ferric chloride to hot water? (A) Due to precipitation of ferric hydroxide there is an excess of Fe3+ ions. (B) Due to preferential adsorption of Fe3+ ions by the sol of Fe(OH)3. (C) Due to absence of any negatively charged ion. (D) Due to adsorption of OH- and Cl- ions, the remaining sol has only Fe3+ ions.

Tardigrade Admin · Accepted Answer

The adsorption of positively charged Fe3+ ions by the sol of hydrated ferric oxide results in positively charged colloid.

Q. Why is ferric hydroxide colloid positively charged when prepared by adding ferric chloride to hot water?

Due to precipitation of ferric hydroxide there is an excess of $F e^{3 +}$ ions.

Due to preferential adsorption of $F e^{3 +}$ ions by the sol of $F e (O H)_{3}$ .

Due to absence of any negatively charged ion.

Due to adsorption of $O H^{-}$ and $C l^{-}$ ions, the remaining sol has only $F e^{3 +}$ ions.

The adsorption of positively charged $F e^{3 +}$ ions by the sol of hydrated ferric oxide results in positively charged colloid.