The correct statement(s) in the balanced equation is(are):

a. H₂S is oxidised.
b. Cl₂ is reduced.
c. H₂S is reduced.
d. Cl₂ is oxidised.

1. a, b
2. b, c
3. c, d
4. a, d

Consider the given reaction:
\(2 \mathrm{Cu}_2 \mathrm{O}(s)+\mathrm{Cu}_2 \mathrm{~S}(s) \rightarrow 6 \mathrm{Cu}(s)+\mathrm{SO}_2(g)\)

Which of the following statements about the given reaction is correct?
1. Cu is reduced and Cu(I) is an reductant.
2. Sulphur is reduced and S in Cu₂S acts as oxidant.
3. Cu(I) is an oxidant and Cu(I) is reduced.
4. Sulphur is reduced and copper is oxidised.

For the reaction:
Fe₃O₄ (s) + Al (s) → Fe (s) + Al₂O₃ (s)
Which of the following statements about the reaction are correct?

1. a, c
2. a, b
3. b, c
4. c, d