The Hinsberg reagent is a chemical used to distinguish primary, secondary, and tertiary amines. It typically consists of benzene sulfonyl chloride. When primary amines react with the Hinsberg reagent, they form a sulfonamide that is soluble in alkali. Secondary amines form a compound that is insoluble in alkali, while tertiary amines do not react with the Hinsberg reagent.
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Alkylamines consist of tetrahedral nitrogen centers where the C-N-H and C-N-C bond angle is 109°. The distance between C-N bonds is smaller in comparison to the C-C range. The amines can also display a chiral property wherein the center of the nitrogen atom holds for replacements which creates solo pairs.
The bond angle in the case of trimethylamine is 108° which results in the Pyramidal structure of trimethylamine-
Aromatic Amine:
Due to the mixture of the solo pair with the aryl substituent, nitrogen nearly has a planar structure in aromatic amines. The C-N range is very short. In aniline, the distance between C-N bonds is similar to the distance between C-C bonds.
