Answer:
Mg(s) + 2H^+(aq) ----> Mg^2+(aq) + H2(g)
Explanation:
We must first write the molecular equation, then obtain the complete ionic equation and subsequently get the net ionic equation as shown below;
Molecular reaction equation;
Mg(s) + 2HCl(aq) ------> MgCl2(aq) + H2(g)
Complete ionic equation;
Mg(s) + 2H^+(aq) + 2Cl^-(aq) ----> Mg^2+(aq) + 2Cl^-(aq) + H2(g)
Net ionic equation;
Mg(s) + 2H^+(aq) ----> Mg^2+(aq) + H2(g)