Question

The nature of charge on resulting colloidal particles when ${\mathrm{FeCl}}_3$ is added to excess of hot water is.

• A. Positive
• B. Neutral
• C. Sometimes positive and sometimes negative
• D. Negative

Answer 1

The correct option is A

Positive

Explanation for the Correct options:-

A. Positive

• When${\mathrm{FeCl}}_3$ is dissolved in the hot water the absorption of the ${\mathrm{Fe}}^{3+}$ ions over the surface the $\mathrm{Fe}{\left(\mathrm{OH}\right)}_3$ takes place and the positively charged sol of the hydrated Ferric hydroxide($\mathrm{Fe}{\left(\mathrm{OH}\right)}_3$) forms.

Explanation for the Incorrect options:-

B. Neutral

• Neutral sols are formed from gold or silver sols.

C. Sometimes positive and sometimes negative

• When${\mathrm{FeCl}}_3$ is dissolved in the hot water positively charged sol of the hydrated Ferric hydroxide $\left({\mathrm{FeOH}}_3\right)$ forms and When${\mathrm{FeCl}}_3$ is dissolved in a Sodium hydroxide ($\mathrm{NaOH}$) then only negatively charged sol is formed.

D. Negative

• When${\mathrm{FeCl}}_3$ is dissolved in a Sodium hydroxide ($\mathrm{NaOH}$) then only negatively charged sol is formed.

Final Answer: Hence, option (A) is correct, i.e. When${\mathrm{FeCl}}_3$ is dissolved in the hot water positively charged sol of the hydrated Ferric hydroxide, $\left({\mathrm{FeOH}}_3\right)$ forms.