If the question ask to state what is reducing or oxidizing agent, we should answer in solid or aqueous phase? Like Ag3+(aq) or Ag(s)?
Answer in solid phase like Ag(s)
Selalunya awak kena tengok either compound dalam phase mana undergoes oxi or reduc
Or else ion which undrrgoes oxi or reduc
Therefore half cell equation is important for each question before identifying