Question

“ Urea contain two NH2 group , but it is a monoacidic base .Account for this fact​

Answer 1

Answer:

Explanation:

UREA formed by combining two ammonia molecules (NH3) with a carbon dioxide (CO2) molecule in the urea cycle.  When it is dissolved in water, it is neither acidic nor basic urea is mono-acidic base. It it  an  Arrhenius base(not a Bronsted-lowry base or a lewis base )  which  deprotonates water leaving OH- in its water solution , which in turn works as base.

the amine group (NH 2)  in urea can accept a hydrogen ion, making it a basic substance. However, the carbonyl group (C=O) offers a significant opportunity for resonance, which will stabilise the amine group. This means, urea is very slightly basic (and very close to neutral).

The pkb is around 13.9  , which makes it  a neutral substance. The pKb

 of a neutral substance is close to 14.0 at RTP. Theoretically, a 0.100 mol $dm^{-3}$    of urea has a pH of 7.05 .

Hope this help :)