Which of the following can be used to get a diazonium fluoroborate? (a) \(\mathrm{p}\) -toluidine (b) Glycine (c) Benzylamine (d) Cyclohexylamine

(Diazonium compounds are a class of organic chemical compounds that share a common functional group R-N2+X- where X is anionic and R is an organic group. The prerequisite for a compound to form a diazonium compound is that it must be an aromatic primary amine. This is due to the unique mechanism of diazonium formation involving the replacement of the primary amino group with a diazonium group.)

(From the set of compounds given, we look for an aromatic primary amine. An aromatic compound is a cyclic, planar molecule with a ring of resonance bonds. A primary amine is an amine that has the general structure -NH2 (nitrogen atom bound to two hydrogen atoms).) (a) p-toluidine, which has the IUPAC name 4-Methylbenzenamine, is an aromatic compound (benzene ring is present) and a primary amine (amino group (-NH2) is attached to the benzene ring). Therefore, p-toluidine can form diazonium fluoroborate when reacted with appropriate reagents. (b) Glycine, or aminoacetic acid, is an amino acid rather than an aromatic amine. So, it cannot form diazonium fluoroborate. (c) Benzylamine, or Phenylmethanamine, is a primary amine but it isn’t an aromatic amine. Therefore, it cannot form a diazonium compound. (d) Cyclohexylamine is not an aromatic compound and therefore it cannot form a diazonium compound.

(Out of the given options, only p-toluidine can be used to get a diazonium fluoroborate as it is the only aromatic primary amine in the list.)