D. MgO + 2HCI – MgCl2 + H20
Further explanation
The chemical equation is said to be balanced if the number of atoms in the reactants is equal to the number of atoms in the product
A. CaO2 + HCl → CaCl2 + H20
atoms O, Cl and H are not the same
B. CO2 + H2O + H2CO2
atoms O are not the same
C. K+ H2O → K20 + H2
atoms K are not the same
D. MgO + 2HCI – MgCl2 + H20
Mg, left = 1, right=1
O, left=1, right=1
H, left=2, right=2
Cl, left=2, right=2
Chemical equation is balanced