Question

While preparing crystals of Mohr's salt, dil. \(H_2 SO_4\) is added to a mixture of ferrous sulphate and ammonium sulphate, before dissolving this mixture in water, dil. \(H_2 SO_4\) is added here to: 

(1) prevent the hydrolysis of ferrous sulphate 

(2) prevent the hydrolysis of ammonium sulphate 

(3) make the medium strongly acidic 

(4) increase the rate of formation of crystals

Answer 1

Correct option is (1) prevent the hydrolysis of ferrous sulphate 

\(Fe^{+2}\) ions undergoes hydrolysis, therefore while preparing aqueous solution of ferrous sulphate and ammonium sulphate in water dilute sulphuric acid is added to prevent hydrolysis of ferrous sulphate.