Given below are two statements: Statement I: Mohr's salt is preferred over hydrated ferrous sulphate as a primary standard in redox titrations because its crystals are resistant to aerial oxidation. Statement II: While preparing an aqueous standard solution of Mohr's salt, a small amount of dilute sulphuric acid is added primarily to prevent the aerial oxidation of Fe ²⁺ ions. In the light of the above statements, ch

Step-by-step solution

Statement I is correct because Mohr's salt, (NH₄)₂Fe(SO₄)₂ 6H₂O , is stable in air and its crystals are resistant to aerial oxidation, unlike hydrated ferrous sulphate which easily oxidizes to ferric sulphate. Statement II is incorrect because while preparing an aqueous standard solution of Mohr's salt, a small amount of dilute sulphuric acid is added primarily to prevent the hydrolysis of Fe²⁺ ions, which would otherwise form a turbid solution of iron(II) hydroxide, not to prevent aerial oxidation. Therefore, Stat