Question

Mohr's salt is dissolved in dil.$H_2{SO}_4$ instead of distilled water to?

• A. Enhance the rate of dissolution
• B. Prevent cationic hydrolysis
• C. Increase the rate of ionisation
• D. Increase its reducing strength

Answer 1

The correct option is B Prevent cationic hydrolysis

Ferrous ions of Mohr's salt undergo hydrolysis in aqueous solution. $\text{to prevent the hydrolysis,}$ Conc. H2SO4 needs to be added to the Mohr's salt crystals during the preparation of its standard solution. Another reason is also to prevent the oxidation of $F{e}^{2+}ions$ of Mohr's salt to $F{e}^{3+}ions.$