Question

When the following equation is balanced properly under acidic conditions, what are the coefficients of the species shown? Zn2+ + NO,— Zn+ NO; Water appears in the balanced equation as a (reactant, product, neither) with a coefficient of (Enter 0 for neither.) Which element is reduced?

Answer 1

Zn in Zn+2 has oxidation state of +2

Zn in Zn has oxidation state of 0

So, Zn in Zn+2 is reduced to Zn

N in NO2 has oxidation state of +4

N in NO3- has oxidation state of +5

So, N in NO2 is oxidised to NO3-

Reduction half cell:

Zn+2 + 2e- --> Zn

Oxidation half cell:

NO2 --> NO3- + 1e-

Balance number of electrons to be same in both half reactions

Reduction half cell:

Zn+2 + 2e- --> Zn

Oxidation half cell:

2 NO2 --> 2 NO3- + 2e-

Lets combine both the reactions.

Zn+2 + 2 NO2 --> Zn + 2 NO3-

Balance Oxygen by adding water

Zn+2 + 2 NO2 + 2 H2O --> Zn + 2 NO3-

Balance Hydrogen by adding H+

Zn+2 + 2 NO2 + 2 H2O --> Zn + 2 NO3- + 4 H+

This is balanced chemical equation in acidic medium

Answer:

1, 2, 1, 2

Water appear as a reactant with coefficient of 2

Zinc is reduced