To balance the chemical equation for these reactions, we can write the following equations:

Mg + Mg(NO3)2 → MgO + 2NO2 + 2Mg(NO3)2Mg(OH)2 + 2HCl → 2MgCl2 + 2H2OMg(OH)2 + 2HCl → MgCl2 + 2H2OMgCl2 + Mg(OH)2 → MgOHCl + MgCl2

For the second set of reactions:

Sn + SnCl2 → SnCl42Sn(OH)2 + 4Na → 2SnO2 + 4NaOHSnSO4 + Na2 → NaSnO2 + Na2SO4

These equations represent the balanced chemical reactions for the given substances.