If the formula of metal nitride is MN, the formula of the metal sulphate is?
M2(SO4)3
From formula of metal nitride MN we find that charge of M is +3 as the charge of nitrogen is -3 and both balance each other to form the formulae MN. Since, we know that charge of sulphate is -2.
Symbol M SO4
Valency 3+ 2-
Criss crossing the valencies, we get M2(SO4)3
Therefore formula of metal sulphate is M2(SO4)3.