Question

K-K2O-K2SO4 ;Mg(OH2)-MgO-Mg3(PO4)2

Answer 1

1)

4K + O2 = 2K2O

K2O + H2SO4 = K2SO4 + H2O

2)

Mg(OH)2 = MgO + H2O

3MgO + 2H3PO4 = 3H2O + Mg3(PO4)2