Question

Balance the following equation: MgO + HCl = MgCl2* + H2*O

Answer 1

Balanced equation :
MgO + 2 HCl = MgCl 2 + H 2O

Answer 2

MgO + HCl = MgCl2* + H2*O

To balance an equation, you have to have both the reactants and products side equal. 

Mg = 1            Mg = 1
H = 1               H = 2
Cl = 1              Cl = 2

MgO + 2HCl = MgCl2 + H2*O

We added the coefficient 2, so they could balance.