Answer:
The chemical substance semicarbazide has the formula H2NNHC(O)NHNH2. It has a mild odour and is a white crystalline powder. Semicarbazide is a reagent extensively used in organic chemistry to determine carbonyl compounds (aldehydes and ketones).
Semicarbazone derivatives are formed when semicarbazide interacts with an aldehyde or ketone in the presence of an acid catalyst. To produce a semicarbazone, the amino group (-NH2) of the semicarbazide is nucleophilically added to the carbonyl group (C=O) of the aldehyde or ketone, followed by the elimination of a water molecule. Semicarbazones are frequently employed in organic chemistry to detect unknown aldehydes and ketones.