Oxidation and reduction的問題(2)

1.
No substance is underlined.
I can only state that which reactant is oxidized and which reactant is reduced in each option.

A.
FeCl2 undergoes reduction because the oxidation number of Fe increases from +2 to +3.
Cl2 undergoes oxidation because the oxidation number of Cl decreases from 0 to -1.

B.
The reaction is NOT redox because there is no change in oxidation number.
No substance undergoes oxidation, and no substance undergoes reduction.

C.
Fe2(SO4)3 undergoes reduction because the oxidation number of Fe decreases from +3 to +2.
KI undergoes oxidation because the oxidation number of I increase from -1 to 0.

D.
NH3 undergoes oxidation because the oxidation number of N increases from -3 to 0.
CuO undergoes reduction because the oxidation number of Cu decreases from +2 to 0.

2.
The answer is D.

(1) is a NOT a redox reaction.
There is no change in oxidation number.

(2) is a redox reaction.
Cl2 is reduced because the oxidation number of Cl decreases from 0 to -1.
NH3 is reduced because the oxidation number of N increases from -3 to 0 (in N2).

(3) is a redox reaction.
Cu is oxidized because the oxidation number of Cu increases from 0 to +2.
H2SO4­ is reduced because the oxidation number of S decreases from +6 to +4 (in SO2).
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