The correct IUPAC name of tert-butyl benzyl ether is
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → tert-Butoxy phenyl methane
In the IUPAC system an ether R–O–R′ is named as an alkoxy derivative of a hydrocarbon: the larger group is taken as the parent hydrocarbon and the smaller one, together with the oxygen, as the alkoxy prefix.
tert-Butyl benzyl ether is \( \ce{C6H5CH2-O-C(CH3)3} \). The two groups are benzyl (\( \ce{C6H5CH2} \)–, seven carbons, i.e. phenylmethyl) and tert-butyl (four carbons). The larger group gives the parent, phenylmethane; the smaller one becomes the prefix tert-butoxy, \( \ce{(CH3)3C-O} \)–. So the name is tert-butoxy phenyl methane, also written (tert-butoxymethyl)benzene.
Why the other options are incorrect
Option (2) 2-methyl-2-phenyl methoxy propane — Incorrect. This takes the smaller tert-butyl part (2-methylpropane) as the parent and the larger benzyl part as the prefix, the reverse of the rule above.
Option (3) 1,1-Dimethyl benzyl methoxy ethane — Incorrect. This name describes an ethane chain carrying a benzyl group, a methoxy group and two extra methyl groups, a different and larger compound. In the real ether the parent is the larger group, phenylmethane, and the smaller group with the oxygen is the prefix tert-butoxy.
Option (4) tert-Butyl methoxy benzene — Incorrect. This describes a benzene ring carrying both a tert-butyl and a methoxy group, a different compound (\( \ce{C11H16O} \) with no \( \ce{CH2-O} \) link).
NCERT (2026-27 edition):
Nomenclature – “… According to IUPAC system of nomenclature, ethers are regarded as hydrocarbon derivatives in which a hydrogen atom is replaced by an –OR or –OAr group, where R and Ar represent alkyl and aryl groups, respectively. The larger (R) group is chosen as the parent hydrocarbon.”