Carbonyl 1st part

Carbonyl Compounds MCQs

1. Which group is present in all carbonyl compounds?

A) –OH

B) –NH₂

C) –C=O

D) –COOH

Answer: C

2. Primary alcohols oxidize to form:

A) Ketones

B) Aldehydes

C) Esters

D) Carboxylic acids

Answer: B

3. Which of the following does NOT oxidize under normal conditions?

A) 1° Alcohol

B) 2° Alcohol

C) 3° Alcohol

D) Aldehyde

Answer: C

4. Which oxidizing agent is mentioned in the notes?

A) PCC

B) KMnO₄

C) Cu/heat

D) H₂O₂

Answer: C

5. Mild reduction of carboxylic acid gives:

A) Alcohol

B) Ketone

C) Aldehyde

D) Alkene

Answer: C

6. In the presence of Ni/Pd + H₂, methanal is reduced to:

A) Ethanol

B) Methanol

C) Formaldehyde

D) Acetone

Answer: B

7. Which is the correct order of reactivity towards nucleophiles?

A) Ketone > Aldehyde > Methanal

B) Aldehyde > Methanal > Ketone

C) Methanal > Aldehyde > Ketone

D) Ketone > Methanal > Aldehyde

Answer: C

8. What reagent is NOT used in nucleophilic addition reaction?

A) HCN

B) NH₄Cl

C) NaHSO₃

D) Grignard reagent

Answer: B

9. What is the product of nucleophilic addition to carbonyl?

A) Alkene

B) Alcohol

C) Alkane

D) Ketone

Answer: B

10. Formaldehyde does NOT react with:

A) Ammonia

B) HCN

C) Grignard reagent

D) Hydrazine

Answer: A

11. Hexamine is formed from:

A) Acetone + NH₃

B) Formaldehyde + NH₃

C) Methanol + NH₃

D) Ethanal + NH₃

Answer: B

12. How many molecules of formaldehyde react with 4 NH₃ to form hexamine?

A) 3

B) 5

C) 6

D) 2

Answer: C

13. 2,4-DNP test is used to identify:

A) Alcohols

B) Carbonyl compounds

C) Ethers

D) Carboxylic acids

Answer: B

14. What color precipitate is observed in a positive 2,4-DNP test?

A) Red

B) Blue

C) Yellow-orange

D) White

Answer: C

15. What does 2,4-DNP form when reacting with aldehydes/ketones?

A) Carboxylic acid

B) Schiff base

C) Yellow oil

D) Oxime

Answer: B

16. Which functional group is present in Schiff bases?

A) –C=O

B) –C=N–

C) –OH

D) –CH₃

Answer: B

17. Which of these can't be differentiated using 2,4-DNP?

A) Aldehyde and Ketone

B) Alcohol and Aldehyde

C) Ketone and Alcohol

D) Acid and Ketone

Answer: A

18. Which test helps form a compound with hexagonal ring and NO₂ group?

A) Benedict's test

B) Tollen's test

C) 2,4-DNP test

D) Fehling's test

Answer: C

19. Grignard reagent adds to carbonyl compounds by:

A) Electrophilic substitution

B) Nucleophilic addition

C) Radical substitution

D) Electrophilic addition

Answer: B

20. What product forms when aldehyde reacts with hydrazine?

A) Amine

B) Alcohol

C) Schiff base

D) Hydrazone

Answer: D

21. Which of these contains NO alpha hydrogen?

A) Acetone

B) Propanone

C) Formaldehyde

D) Ketone

Answer: C

22. In ozonolysis of alkenes, the products are:

A) Alcohols

B) Aldehyde & Ketone

C) Carboxylic acids

D) Alkanes

Answer: B

23. During mild reduction, which catalyst is used?

A) PdCl₂

B) Cu

C) Ni/Pd + BaSO₄

D) MnO₂

Answer: C

24. What group does 2,4-DNP specifically detect?

A) Carboxyl group

B) Hydroxyl group

C) Carbonyl group

D) Alkene group

Answer: C

25. In the presence of excess H₂, what happens to CH₂=CH₂?

A) Becomes CH₃CH₃

B) Turns into CH₂OH

C) Oxidizes to acid

D) No reaction

Answer: A

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