Question

what to add
of urea to from ammonia​

Answer 1

Explanation:

.........................

Answer 2

Answer:

Explanation:

accounts for more than fifty percent of the world's nitrogenous fertilizers.[1] It is found in granular or prill form, which allows urea to be easily stored, transported and applied in agricultural settings. It is also the cheapest form of granular nitrogen fertilizer. Since urea is not an oxidizer at standard temperature and pressure, it is safer to handle and less of a security risk than other common nitrogen fertilizers, such as ammonium nitrate. However, if urea is applied to the soil surface, a meaningful fraction of applied fertilizer nitrogen may be lost to the atmosphere as ammonia gas; this only occurs under certain conditions.

Breakdown of urea

For plants to absorb nitrogen from urea it must first be broken down:

{\displaystyle (NH_{2})_{2}CO+H_{2}O{\stackrel {urease}{\rightarrow }}NH_{3}+H_{2}NCOOH\rightarrow 2NH_{3(gas)}+CO_{2(gas)}}{\displaystyle (NH_{2})_{2}CO+H_{2}O{\stackrel {urease}{\rightarrow }}NH_{3}+H_{2}NCOOH\rightarrow 2NH_{3(gas)}+CO_{2(gas)}}[2]

Urease is a naturally occurring enzyme that catalyzes the hydrolysis of urea to unstable carbamic acid. Rapid decomposition of carbamic acid occurs without enzyme catalysis to form ammonia and carbon dioxide.[2][3] The ammonia will likely escape to the atmosphere unless it reacts with water to form ammonium (NH4+) according to the following reaction:

{\displaystyle NH_{3(gas)}+H_{2}O\rightarrow NH_{4}^{+}+OH^{-}}{\displaystyle NH_{3(gas)}+H_{2}O\rightarrow NH_{4}^{+}+OH^{-}}

This is important because ammonium is a plant available source of nitrogen while ammonia is not.[4] Additionally, the formation of the hydroxide ion may cause soils around the applied urea particle to have a pH around 9.0 which increases ammonia volatilization. This area is also highly toxic due to elevated ammonia concentration for several hours so it is recommended that urea based fertilizers not be applied or banded with planted seed at a rate that exceeds 10–20 kg/ha, depending on the crop species.[5] It is important that there is adequate moisture because up to thirty percent of the available nitrogen can be lost through atmospheric volatilization within seventy-two hours of application.[6]

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