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Class 12 Chemistry (Part Ii) Chapter 12 Aldehydes Quiz 8 (25 MCQs)

Quiz Instructions

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1. Which reagent is used to distinguish between aldehydes and ketones?

Correct Answer: B) Tollen's reagent.

2. How do you produce a carboxylic acid?

Correct Answer: B) Oxidizing a primary alcohol or an aldehyde.

3. The simplest ketone has

Correct Answer: C) Three carbon atoms.

4. When reacted with a strong reducing agent, ketones turn into

Correct Answer: D) Secondary alcohols.

5. When performing recrystallisation to purify crystals, on what basis is the solvent selected?

Correct Answer: A) The crystals have a high solubility in hot solvent but a low solubility in cold solvent.

6. What is the hybridization and geometry of aldehydes and ketones carbons?

Correct Answer: A) Sp2 and trigonal planar.

7. Which of the following alcohols can be oxidised to 2-methyl-3-pentanone?

Correct Answer: D) (CH$_{3}$)$_{2}$CHCH(OH)CH$_{2}$CH$_{3}$.

8. Which substance gives a positive Tollen's test?

Correct Answer: B) Ethanal.

9. Which type of carboxylic acid reduction leads to the formation of ketones?

Correct Answer: B) Reduction of carboxylic acids to ketones is typically achieved using milder reagents like DIBAL-H or borane.

10. What is the result of the hydration of alkynes in terms of functional groups?

Correct Answer: B) Ketones.

11. Which general conclusion can be drawn about carboxylic acids from these reactions?

Correct Answer: C) They show acidic properties.

12. The compound with highest boiling point in the following is .....

Correct Answer: B) Butanoic acid.

13. What is the product formed when an aldehyde reacts with a primary amine?

Correct Answer: D) Imines.

14. CH$_{3}$COCl + H$_{2 }$in presence of Pd/BaSO$_{4}$$\rightarrow$

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

15. Which substance would test positively with 2, 4-DNPH but negatively with Tollens' reagent?

Correct Answer: B) Propanone.

16. What is the correct formula of the reducing agent used to reduce aldehydes and ketones?

Correct Answer: A) LiAlH$_{4}$.

17. Compare the boiling point of ethanal and ethane.

Correct Answer: D) Ethanal is higher because it is polar with stronger intermolecular forces.

18. What is the functional group of ketones?

Correct Answer: B) $-CO-$.

19. What is the common name for ethanoic acid?

Correct Answer: B) Acetic acid.

20. When reacted with an oxidising agent, secondary alcohols turn into

Correct Answer: B) Ketones.

21. What type of reactions can Grignard reagents undergo to form aldehydes or ketones?

Correct Answer: C) Nucleophilic addition reactions with carbonyl compounds.

22. Which functional group represent the aldehyde group.

Correct Answer: B) R-CHO.

23. Fehling's solution will turn:

Correct Answer: B) Blue-brick red.

24. Aldehyde or ketone to alcohol

Correct Answer: D) NaBH4 in aqueous ethanol at room temperature.

25. Tollens' reagent shows the following colour change in a ketone

Correct Answer: C) Stays colourless.

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