Practice free Chemistry NEET multiple-choice questions online with instant answers and detailed explanations. No login required.
The Williamson synthesis involves the reaction between:
The NCERT explicitly defines Williamson synthesis as, 'In this method, an alkyl halide is allowed to react with sodium alkoxide. R–X + Na+–O’R' → R–O–R + Na+X'.'
Why is bimolecular dehydration not appropriate for the preparation of ethyl methyl ether?
If a mixture of ethyl alcohol and methyl alcohol were used for bimolecular dehydration, it would lead to a mixture of three possible ethers: diethyl ether, dimethyl ether, and ethyl methyl ether, making the separation difficult and the yield of the desired unsymmetrical ether low. This is an application of the understanding that SN2 dehydration with a mixture of alcohols is not selective.
What is the primary product when $\text{CH}_3\text{CH}_2\text{Br}$ reacts with $\text{CH}_3\text{ONa}$?
This is a direct application of the Williamson synthesis, where a primary alkyl halide ($\text{CH}_3\text{CH}_2\text{Br}$) reacts with a sodium alkoxide ($\text{CH}_3\text{ONa}$) via an $\text{S}_{\text{N}}2$ reaction to form an ether, methyl ethyl ether ($\text{CH}_3\text{CH}_2\text{OCH}_3$).
Which of the following methods is NOT mentioned in the NCERT text as a preparation method for ethers?
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.
In the dehydration of alcohol for ether synthesis, keeping the temperature low is crucial because:
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).
Which of the following compounds is mentioned as an inhalation anaesthetic that has been largely replaced due to slow effect and unpleasant recovery?
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.'
Which of the following statements accurately describes the hybridization and geometry of the carbonyl carbon atom?
According to the NCERT text, 'The carbonyl carbon atom is sp2-hybridised and forms three sigma (s) bonds... The bond angles are approximately 120° as expected of a trigonal coplanar structure.' This directly indicates sp2 hybridization and trigonal planar geometry.
The carbon-oxygen double bond in a carbonyl group is polarised due to:
The context clearly states, 'The carbon-oxygen double bond is polarised due to higher electronegativity of oxygen relative to carbon.'
Based on the polarity of the carbonyl group, which statement is correct regarding the nature of the carbonyl carbon and oxygen atoms?
The NCERT text explains, 'Hence, the carbonyl carbon is an electrophilic (Lewis acid), and carbonyl oxygen, a nucleophilic (Lewis base) centre.'
Carbonyl compounds have substantial dipole moments. This property indicates that they are:
The context mentions, 'Carbonyl compounds have substantial dipole moments and are polar than ethers.' This directly compares their polarity relative to ethers.
Ready to ace NEET?
Free access · No credit card required
Yes. You can attempt every Chemistry question on this page for free without logging in, and check the correct answer with a detailed explanation instantly.
No account is required to attempt questions and view answers. A free account adds bookmarks, personal notes, and progress tracking.
The bank mixes NEET previous year questions (PYQs) with practice questions, each tagged with its exam appearances where applicable.