JEE · Chemistry · Aldehydes, Ketones & Carboxylic Acids doubts
12 doubts found
How can a simple test tube reaction tell an aldehyde apart from a ketone?
Aldehydes are easily oxidised, ketones are not — and two tests exploit this.
Why are aldehydes generally more reactive than ketones towards nucleophiles?
The carbonyl carbon is the reactive spot, and two effects make aldehydes more open to attack.
Why is acetic acid (vinegar) a stronger acid than phenol or ethanol?
When a carboxylic acid loses its O–H proton, the negative charge on the carboxylate is shared equally over two oxygen atoms by resonance, giving a very stable ion — so the acid readily gives up its proton.
Why does a carboxylic acid have a much higher boiling point than an alcohol of similar mass?
Carboxylic acids form especially strong hydrogen bonds — in fact two molecules pair up into a cyclic 'dimer' held by two hydrogen bonds, effectively doubling the particle size.
What does “Nucleophilic addition to carbonyls” actually mean in Aldehydes, Ketones & Carboxylic Acids, and why does it matter for JEE?
the polar C=O group is attacked by nucleophiles at carbon; aldehydes react faster than ketones.
I keep getting “Nucleophilic addition to carbonyls” questions wrong in Aldehydes, Ketones & Carboxylic Acids. What's the trap?
thinking ketones are more reactive than aldehydes.
What does “Acidity of carboxylic acids” actually mean in Aldehydes, Ketones & Carboxylic Acids, and why does it matter for JEE?
carboxylic acids are more acidic than alcohols and phenols because the carboxylate ion spreads its charge over two equivalent oxygens.
I keep getting “Acidity of carboxylic acids” questions wrong in Aldehydes, Ketones & Carboxylic Acids. What's the trap?
ranking phenol as more acidic than a carboxylic acid.
What is the difference between aldehyde and ketone?
An aldehyde has the carbonyl at the end of the chain (at least one H on it) and is easily oxidised; a ketone has the carbonyl in the middle (two carbon groups) and resists mild oxidation.
What is the difference between Tollens' test and Fehling's test?
Both detect aldehydes: Tollens' gives a silver mirror, Fehling's gives a red-brown Cu₂O precipitate — ketones give a negative result in both.
How is Aldehydes, Ketones & Carboxylic Acids tested in JEE, and what should I focus on?
Prioritise the core ideas: Nucleophilic addition to carbonyls, Acidity of carboxylic acids.
What are the most common mistakes students make in Aldehydes, Ketones & Carboxylic Acids?
aldehydes are less hindered and more electrophilic at the carbonyl carbon, so they undergo nucleophilic addition faster than ketones.