Match the nitrogen atom in Column I with its hybridisation in Column II. Column I: P = pyridine, Q = pyrrole, R = acetonitrile ( $CH X_{3} CN$ ), S = piperidine (saturated six-membered amine). Column II: 1 = $s p$ , 2 = $s p^{2}$ , 3 = $s p^{3}$ .

Answer: D

Pyridine N is in an aromatic ring with a double bond (

s p^{2}

). Pyrrole N donates its lone pair into the aromatic sextet and is trigonal planar (

s p^{2}

). The nitrile N is triply bonded (

s p

) and piperidine N has three single bonds plus a lone pair (

s p^{3}