What's the correct answer to this?

Question

Are any of these equations redox reactions? if so what are their reducing and oxidizing agents?

CuSO₄(aq)+Zn(s)→ZnSO₄(aq)+Cu(s)

HCl(aq)+NH₃(aq)→NH₄Cl(aq)

2Ca(s)+O₂(g)→2CaO(s)

Answer 1

CuSO₄(aq)+Zn(s)→ZnSO₄(aq)+Cu(s) - redox

CuSO4 is the oxidizing agent. ZnSO4 is the reducing agent.

HCl(aq)+NH₃(aq)→NH₄Cl(aq) - not redox

2Ca(s)+O₂(g)→2CaO(s) -redox

Ca is the reducing agent. O2 is the oxidizing agent.