NEET Practice Questions (MCQs) with Answers & Solutions

In $CH_3CH=CHC(Br)(CH_3)_2$, the double bond is between two carbons, and the bromine is attached to a carbon atom that is one carbon away from the double bond ($sp^3$ hybridised carbon next to an $sp^2$ carbon of the double bond). This fits the definition of an allylic halide: 'These are the compounds in which the halogen atom is bonded to an sp3-hybridised carbon atom adjacent to carbon-carbon double bond (C=C).'

According to Table 6.1 in the NCERT text, the common name 'neo-Pentyl bromide' corresponds to the IUPAC name '1-Bromo-2,2-dimethylpropane'.

The NCERT text defines geminal halides or gem-dihalides as compounds 'when both the halogen atoms are present on the same carbon atom of the chain'. 1,1-Dibromoethane has both bromine atoms on the same carbon.

The NCERT text states: 'In common name system, gem-dihalides are named as alkylidene halides and vic-dihalides are named as alkylene dihalides.'

The NCERT text describes aryl halides as 'compounds in which the halogen atom is directly bonded to the sp2-hybridised carbon atom of an aromatic ring.' Also, the introductory text mentions 'haloarenes contain halogen atom(s) attached to sp2 hybridised carbon atom(s) of an aryl group.'

The NCERT text states: 'Similarly, if halogen is attached to secondary or tertiary carbon atom, the alkyl halide is called secondary alkyl halide (2°) and tertiary (3°) alkyl halide, respectively.' A tertiary carbon atom is bonded to three other carbon atoms.

The introductory text mentions: 'Haloalkanes contain halogen atom(s) attached to the sp3 hybridised carbon atom of an alkyl group'.

According to Table 6.1 in the NCERT text, the common name for $CH_2Cl_2$ is 'Methylene chloride'.

The NCERT text defines benzylic halides as 'compounds in which the halogen atom is bonded to an sp3-hybridised carbon atom attached to an aromatic ring.' From Table 6.1, 'Benzyl chloride' is given as an example with the structure C6H5CH2Cl, where Cl is attached to an $sp^3$ carbon adjacent to the benzene ring.

This structure is 2-Chloro-3-methylbutane. The longest carbon chain is 4 carbons long (butane). The chlorine is on the second carbon, and a methyl group is on the third carbon, following IUPAC rules for naming alkyl halides as halosubstituted hydrocarbons. The example '2-Bromo-3-methylbutane' for (CH3)2CHCHBrCH3 in the text confirms this logic.