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Class 12 Chemistry (Part Ii) Chapter 12 Aldehydes Quiz 3 (25 MCQs)

Quiz Instructions

Select an option to see the correct answer instantly.

1. The solution used to preserve biological specimen is

Correct Answer: B) Formalin.

2. Which of the following statements about synthesis of aldehydes is CORRECT?

Correct Answer: D) All of above.

3. Boiling points of carboxylic acids is higher than those of their corresponding alcohols due to

Correct Answer: C) Strongly hydrogen bonded dimers.

4. Which of the following statements about aldehydes and ketones is INCORRECT?

Correct Answer: B) Aldehydes have a higher boiling point than ketones with similar chain lengths.

5. Aldehyde carbonyl group is always positioned at

Correct Answer: C) End of the chain.

6. How can a primary alcohol be oxidized to form an aldehyde?

Correct Answer: C) Using an oxidizing agent such as PCC or CrO3 in an appropriate solvent.

7. To differentiate between pentan-2-one and penta-3-one a test is carried out. Which of the following is the correct answer?

Correct Answer: B) Pentan-2-one will give iodoform test.

8. Tollen's reagent is used to identify the presence of aldehyde by giving the result of

Correct Answer: B) Silver mirror.

9. Aldehydes are easily oxidized to carboxylic acids by the same reagent which is:

Correct Answer: A) Acidic dichromatic.

10. Which type of carboxylic acid reduction leads to the formation of aldehydes?

Correct Answer: C) LiAlH4 or NaBH4 reduction.

11. Which of the following reactions involves the conversion of an aldehyde to a carboxylic acid?

Correct Answer: A) Oxidation.

12. When nucleophilic addition to the carbonyl group occurs, the carbon attacked undergoes what hybridization change?

Correct Answer: A) Sp2 to sp3.

13. Which of the following reactions are not used to reduce aldehydes to hydrocarbons

Correct Answer: C) Rosenmund reduction.

14. Which is an application of the Tollens' silver mirror test in organic chemistry.

Correct Answer: C) To distinguish between aldehydes and ketones in organic chemistry.

15. HVZ reaction is used to prepare

Correct Answer: A) Alpha Halo acids.

16. Formaldehyde, a common disinfectant, has the formula:

Correct Answer: A) HCHO.

17. What is the product of the oxidation of a ketone?

Correct Answer: B) Carboxylic acid.

18. The acid that does not contain carboxylic group is

Correct Answer: C) Picric acid.

19. C$_{6}$H$_{6}$ + CO + HCl$\rightarrow$

Correct Answer: A) C$_{6}$H$_{5}$CHO.

20. Below are the reagents and conditions used for reduction except

Correct Answer: B) KMnO$_{4}$, H$^{+}$, heat.

21. Which of the following is the most acidic?

Correct Answer: C) Ethanoic acid.

22. CH$_{3}$CHO + dil. NaOH$\rightarrow$

Correct Answer: A) CH$_{3}$CH(OH)CH$_{3}$CHO.

23. Which reagent is commonly used to convert carboxylic acids into acid chlorides?

Correct Answer: B) SOCl$_{2}$.

24. How can carboxylic acids be reduced to alcohols?

Correct Answer: A) By using reducing agents such as lithium aluminum hydride (LiAlH4) or sodium borohydride (NaBH4).

25. When a primary alcohol reacts with acidified dichromate:

Correct Answer: B) There is a colour change from orange to green.

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