Question

The correct sequence of overall biochemical reaction which expresses the process of denitrification is _________.

• A. ( 2NO_3^- \rightarrow 2NO_2^- \rightarrow N_2O \rightarrow 2NO \rightarrow N_2 \)
• B. ( 2NO_3^- \rightarrow 2NO_2^- \rightarrow 2NO \rightarrow N_2O \rightarrow N_2 \)
• C. ( 2NO_3^- \rightarrow 2NO \rightarrow 2NO_2^- \rightarrow N_2O \rightarrow N_2 \)
• D. ( 2NO_3^- \rightarrow N_2O \rightarrow 2NO \rightarrow 2NO_2^- \rightarrow N_2 \)

Hint:

Denitrification reduces nitrate to nitrogen gas via a sequence of intermediates, including nitrite, nitric oxide, nitrous oxide, and finally nitrogen gas.

Answer 1

The Correct Option is B

Step 1: Understanding denitrification.
Denitrification is the biochemical process where nitrate (NO₃⁻) is reduced to nitrogen gas (N₂) by a series of intermediates. The reaction typically involves the sequential reduction of nitrate to nitrite, then to nitric oxide (NO), nitrous oxide (N₂O), and finally to nitrogen gas (N₂).

Step 2: Analyzing the options.
- (A) Incorrect, as this sequence does not represent the typical steps of denitrification.
- (B) Correct, as it follows the correct sequence of denitrification reactions.
- (C) Incorrect, as this sequence does not properly reflect the reduction steps.
- (D) Incorrect, as this sequence misplaces the intermediates of the denitrification process.

Step 3: Conclusion.
Thus, the correct answer is (B) \( 2NO_3^- \rightarrow 2NO_2^- \rightarrow 2NO \rightarrow N_2O \rightarrow N_2 \).