Chapter 18, Problem 2STP

Interpretation Introduction

Interpretation: The compound or ion needs to be identified in which oxidation state of nitrogen is -3.

Concept introduction: The change in oxidation state explains the gain or loss of electrons in the oxidation−reduction reactions.

Answer to Problem 2STP

Correct options are B and D.

Explanation of Solution

B. ${\text{NI}}_{\text{3}}$ , Iodine is less electronegative than nitrogen. Thus oxidation state of iodine is +1 and oxidation state of nitrogen is -3.

D. Hydrogen is less electronegative than nitrogen. In ${\text{NH}}_{\text{3}}$ oxidation state of hydrogen is +1 and oxidation state of nitrogen is -3.

Conclusion

A. ${\text{N}}_{\text{2}}$ , In uncombined state, oxidation state of element is zero. Thus, oxidation state ofN in ${\text{N}}_{\text{2}}$ is zero.

C. ${\text{NO}}_2$ , Nitrogen is less electronegative than oxygen. Thus oxidation state of nitrogen is positive in this case and cannot be -3.