Question

Why to add h2so4 to prepare ferrous ammonium sulfate solution?

Answer 1

$\huge\boxed {ANSWER}$

For preparation of standard solution of Mohr salt {FeSO4.(NH4)2SO4.6H2O}, it's necessary to add dilute H2SO4 to prevent the Fe2+ ions of Mohr salt solution from undergoing oxidation (to Fe3+).

Answer 2

to prepare the standard solution of Mohr salt {FeSO4.(NH4)2SO4.6H2O} it is necessary to add dilute H2SO4 and prevent the Fe2+ ions of the Mohr salt solution from undergoing oxidation to Fe3+.