Question

Draw the structure of the semicarbazone of acetone.

Hint:

Semicarbazones are solid crystalline derivatives of aldehydes and ketones and are frequently used for identification purposes because of their sharp melting points.

Answer 1

Concept: Aldehydes and ketones react with semicarbazide \((NH_2NHCONH_2)\) to form crystalline derivatives known as semicarbazones. This reaction is a nucleophilic addition-elimination reaction and is commonly used for the identification and characterization of carbonyl compounds. Acetone is a ketone having the structure: \[ CH_3COCH_3 \] The carbonyl oxygen is replaced by the semicarbazone group \((=NNHCONH_2)\).

Step 1: Write the reaction \[ CH_3COCH_3 + NH_2NHCONH_2 \rightarrow CH_3C(=NNHCONH_2)CH_3 + H_2O \]

Step 2: Structure of semicarbazone The product obtained is acetone semicarbazone. \[ \boxed{ CH_3 \; \overset{}{\underset{}{|}} \; C=NNHCONH_2 \; \overset{}{\underset{}{|}} \; CH_3 } \] or \[ \boxed{ (CH_3)_2C=NNHCONH_2 } \]

Final Answer \[ \boxed{ (CH_3)_2C=NNHCONH_2 } \]