During the preparation of Mohr's salt solution (Ferrous ammonium sulphate), which of the following acid is added to prev…

Mohr’s salt (ferrous ammonium sulphate) is commonly dissolved in slightly acidic solution (using dilute H₂SO₄) to prevent oxidation and hydrolysis of Fe²⁺ ions. The acidic medium suppresses Fe²⁺→Fe³⁺ conversion and formation of insoluble iron hydroxides, ensuring the stable, clear solution of Mohr’s salt.