A white crystalline precipitate forms when Na2HPO4 is added to a solution containing NH4Cl and excess NH4OH (after groups I to V have been removed). The precipitate is

JEE Main levelSingle correct optionDifficulty 2 of 3qc018

A white crystalline precipitate forms when $Na X_{2} HPO X_{4}$ is added to a solution containing $NH X_{4} Cl$ and excess $NH X_{4} OH$ (after groups I to V have been removed). The precipitate is

Mg X^{2 +} + NH X_{4} X^{+} + HPO X_{4} X^{2 -} + OH X^{-} Mg (NH X_{4}) PO X_{4} + H X_{2} O

, magnesium ammonium phosphate, is the group VI confirmation. Under these conditions

Mg (OH) X_{2}

is held in solution by

NH X_{4} Cl

, and

Al X^{3 +}

was removed in group III.