Alcohol, phenol & ether MCQs for NEET — Chemistry Questions with Answers

The NCERT text explicitly lists '1. By dehydration of alcohols' and '2. Williamson synthesis' under '7.6.1 Preparation of Ethers'. It mentions '3. From Grignard reagents' as a method for preparing ALCOHOLS, not ethers (Section 7.4.1 for alcohols). Option 4 is a restatement of Williamson synthesis.

The NCERT states, 'The alkyl group should be unhindered and the temperature be kept low. Otherwise the reaction favours the formation of alkene.' This indicates that higher temperatures promote elimination (alkene formation) over substitution (ether formation).

A side note in the NCERT text mentions, 'Diethyl ether has been used widely as an inhalation anaesthetic. But due to its slow effect and an unpleasant recovery period, it has been replaced, as an anaesthetic, by other compounds.'

According to the NCERT text, 'The –OH group attached to the benzene ring activates it towards electrophilic substitution. Also, it directs the incoming group to ortho and para positions in the ring as these positions become electron rich due to the resonance effect caused by –OH group.' Therefore, directing to meta positions is incorrect.

The NCERT states: 'With dilute nitric acid at low temperature (298 K), phenol yields a mixture of ortho and para nitrophenols.'

As per the NCERT text, 'The ortho and para isomers can be separated by steam distillation. o-Nitrophenol is steam volatile due to intramolecular hydrogen bonding while p-nitrophenol is less volatile due to intermolecular hydrogen bonding which causes the association of molecules.'

The NCERT states: 'With concentrated nitric acid, phenol is converted to 2,4,6-trinitrophenol. The product is commonly known as picric acid.'

The NCERT notes, '2, 4, 6 - Trinitrophenol is a strong acid due to the presence of three electron withdrawing –NO$_2$ groups which facilitate the release of hydrogen ion.'

According to the NCERT, in Kolbe's reaction, 'Phenoxide ion generated by treating phenol with sodium hydroxide is even more reactive than phenol towards electrophilic aromatic substitution. Hence, it undergoes electrophilic substitution with carbon dioxide, a weak electrophile.'

The NCERT text states: 'Ortho hydroxybenzoic acid is formed as the main reaction product' in Kolbe's reaction.