Question

Stable compound formed during urea hydrolysis

• A. Ammonium hydroxide
• B. Ammonium crbamate
• C. Ammonia
• D. Ammonium carbonate

Hint:

Urea hydrolysis causes a temporary localized increase in soil pH due to the alkalinity of the ammonium carbonate formed.

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
Urea (\(\text{CO(NH}_2)_2\)) applied to the soil undergoes biochemical enzymatic hydrolysis catalyzed by the extracellular enzyme urease.

Step 2: Detailed Explanation:
The hydrolysis of urea occurs in a sequence of reactions:
Urea initially reacts with water to form the unstable intermediate compound, ammonium carbamate:
\[ \text{CO(NH}_2)_2 + \text{H}_2\text{O} \xrightarrow{\text{urease}} \text{NH}_2\text{COONH}_4 \quad (\text{Ammonium carbamate}) \]
Ammonium carbamate is highly unstable and rapidly hydrolyzes further to form a more stable intermediate compound, ammonium carbonate:
\[ \text{NH}_2\text{COONH}_4 + \text{H}_2\text{O} \rightarrow (\text{NH}_4)_2\text{CO}_3 \quad (\text{Ammonium carbonate}) \]
This stable ammonium carbonate eventually dissociates into ammonia (\(\text{NH}_3\)), carbon dioxide (\(\text{CO}_2\)), and water under open atmospheric conditions.
Among the chemical intermediates formed directly in the hydrolysis pathway, ammonium carbonate is the most stable compound before final dissociation.

Step 3: Final Answer:
Thus, Ammonium carbonate is the stable compound formed during urea hydrolysis.