Question

Bi(s) + 4 HNO3(aq) → Bi(NO3)3(aq) + 2 H2O(l) + NO(g)
What is the element being reduced and oxidized?

Answer 1

Oxidation state of bismuth on left hand side is 0 and on right hand side is +3 I.e; the oxidation number increased.

As u know that increase in oxidation number implies oxidation.

What do u think, bismuth oxidized or reduced ?

Answer 2

Oxidation state of nitrogen on left hand side is +5 and on right hand side it is +2 which means oxidation number decreased.

U know that oxidation number decrement implies reduction.

Answer 3

Can you guess now which element oxidized and which reduced?

Answer 4

So nitrogen is being reduced and bismuth is being oxidized?

Answer 5

What about for CuS(aq) + 10 HNO3(aq) → Cu(NO3)2(aq) + H2SO4(aq) + 8 NO2(aq) + 4 H2O(l) ?

Answer 6

The oxidation number of sulphur on left hand side is -2 and on right hand side is +6 which means oxidation number increased.

Answer 7

On left hand side the oxidation number of nitrogen is +5 and on right hand side it is +4 which implies the oxidation number decreased

Answer 8

HNO3 oxidation number of nitrogen is +5.
NO2 oxidation number of nitrogen is +4

Answer 9

So then N being reduced and S being oxidized

Answer 10

C2H6(l) + 12 CoF3(aq) → C2F6(aq) + 6 HF(aq) + 12 CoF2(aq)
For this one I got C being oxidized and Co being reduced. Is this right?

Answer 11

U r right