Question

Which of the following changes exhibit that nitrogen undergoes oxidation?

• A. $\text{NH}_4^+ \rightarrow \text{N}_2$
• B. $\text{NO}_3^- \rightarrow \text{NO}$
• C. $\text{NO}_2 \rightarrow \text{NO}_2^-$
• D. $\text{NO}_3^- \rightarrow \text{NH}_4^+$

Hint:

Remember: Oxidation $\rightarrow$ Increase in oxidation number

Answer 1

The Correct Option is A

Concept: Oxidation = Increase in oxidation number.

Step 1: Calculate oxidation states.
• (A) $\text{NH}_4^+$: N = $-3$ $\rightarrow \text{N}_2$: N = $0$ Increase $\Rightarrow$ oxidation
• (B) $\text{NO}_3^-$: N = $+5$ $\rightarrow \text{NO}$: N = $+2$ Decrease $\Rightarrow$ reduction
• (C) $\text{NO}_2$: N = $+4$ $\rightarrow \text{NO}_2^-$: N = $+3$ Reduction
• (D) $\text{NO}_3^-$: N = $+5$ $\rightarrow \text{NH}_4^+$: N = $-3$ Reduction

Step 2: Conclusion.
Only option (A) shows increase in oxidation state. Final Answer: Option (A)