CBSE Class 12 Chemistry Aldehyde Ketones Carboxylic Acid Exam Notes

CBSE Class 12 Chemistry Aldehyde Ketones Carboxylic Acid Exam Notes. Please refer to the examination notes which you can use for preparing and revising for exams. These notes will help you to revise the concepts quickly and get good marks.

REASONINGS

Q1.Dipole moment of Aldehyde/Ketone is more than Alcohols.
Ans.In aldehyde/Ketone carbonyl group (C = O) has p-electrons which are loosly held and shifts towards oxygen more thas electrons in Alcohols.

Q2.Aldehydes are more reactive than ketones towards nucleophlic substitution.
Ans.(a)Ketone has two alkyl group (+ I effect) makes less polar  bond.
(b)Heavy alkyl group in ketones show stric hindrance and become less reactive.
 

Q3.Benzaldehyde gives tollen’s test but not with fehling solution

Ans.Benzene ring show +R effect in benzaldehyde and make   more polar hence became strong oxidising agent which is only oxidise by strong tollen’s reagent but not with weak oxidsing agent like feliling solution.

Q4.p-fluorobenzoic acid is weaker acid than p-chlorobenzoic acid.
Ans.In p-flurobenzoic acid +R effect outweighs the – I effect of flurine (small size of 2p-orbital electron). But the pchlorobenzoic acid – I effect is more dominating (size of Cl atom 3p electrons) than +R effect.

Q5.Why carboxylic acid do not give the characteristics rection of carbonyl group > C = O.
Ans.In carboxylic acid the resonance structure makes it less electrophilic character than carbonyl group of aldehyde/ ketones.

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