NEET Aldehydes Ketones and Carboxylic Acids — Set 20

Question 1

Which compound gives a positive Fehling’s test but not an iodoform test?

Accepted Answer

Butanal ($ \ce{CH3CH2CH2CHO} $) is an aliphatic aldehyde (positive Fehling’s test) but lacks a $ \ce{CH3C=O} $ group (negative iodoform test).

Question 2

Which of the following aldehydes gives a positive iodoform test?

Accepted Answer

The iodoform test is positive for compounds with a $ \ce{CH3CH(OH)-} $ or $ \ce{CH3C=O} $ group. Ethanal ($ \ce{CH3CHO} $) forms $ \ce{CH3CH(OH)I} $ with iodine and base, giving a yellow precipitate.

Question 3

What is the product when ethanoic acid is heated with calcium hydroxide?

Accepted Answer

Heating the calcium salt of ethanoic acid ($ \ce{(CH3COO)2Ca} $) decarboxylates it to form acetone ($ \ce{CH3COCH3} $).

NEET Chemistry: Aldehydes Ketones and Carboxylic Acids — Practice Set 20

Q1. Which compound gives a positive Fehling’s test but not an iodoform test?

Q2. Which of the following aldehydes gives a positive iodoform test?

Q3. What is the product when ethanoic acid is heated with calcium hydroxide?

Q4. What is the IUPAC name of \( \ce{CH3CH2CH(CHO)CH3} \)?

Q5. What is the product when acetophenone is oxidized with \( \ce{SeO2} \)?

Q6. Which test gives a yellow precipitate with butan-2-one?

Q7. Which method is used to prepare ketones from carboxylic acids?

Q8. Arrange in increasing order of boiling points: Ethanal, Ethanol, Acetone.

Q9. What is the common name of \( \ce{CH3CH2COOH} \)?

Q10. Which compound forms a six-carbon ketone when its calcium salt is heated?