Chapter 20, Problem 2STP

Interpretation Introduction

Interpretation: The pairs that have higher oxidation number, nitrogen-containing ions, or nitrogen compound is to be chosen from the given options.

Concept Introduction: The oxidation number of the element is allocated based on the number of electrons gained or lost by the atom.

Answer to Problem 2STP

Correct answer: The correct option is ‘C’.

Explanation of Solution

Reason for correct option: In option I, the oxidation number of ${\text{NH}}_4$ is $\text{+1}$ (Nitrogen ion) which is greater than ${\text{N}}_2{\text{H}}_4$ , that is $-\text{2}$ (Nitrogen compound).

In option III the oxidation number of ${\text{NO}}_2{}^{-}$ is $\text{+4}$ which is greater than ${\text{N}}_2\text{O}$ , that is $\text{+1}$ .

Therefore, equations I and III have a higher oxidation number of nitrogen ion than the nitrogen compound.

Conclusion

Reasons for incorrect options:

Option A is incorrect: Because equation I and II in both, the oxidation number of nitrogen ion is greater than the compound.

Option B is incorrect: In equation II, ${\text{NO}}_3^{-}$ is $-\text{2}$ which is lesser than ${\text{N}}_2{\text{O}}_4$ , that is $\text{+4}$ , here the nitrogen compound’s oxidation number is more than the nitrogen ion.

Option D is incorrect: Because equation III agrees to the question statement but not in II.

Option E is incorrect: Because equation I and III agrees to the question statement but not equation II.