Sample Quizzes For Preparation: Nitrogen Compounds

AS Level Chemistry – Chapter 19: Nitrogen Compounds Quiz

Question 1: What is formed when a halogenoalkane reacts with excess ammonia in ethanol under pressure?

A. Alkene
B. Nitrile
C. Primary amine
D. Carboxylic acid

Question 2: What is the role of ethanol in the preparation of amines?

A. Acts as an oxidising agent
B. Prevents hydrolysis of halogenoalkane
C. Acts as a nucleophile
D. Prevents substitution by water

Question 3: What type of reaction occurs when a halogenoalkane reacts with ammonia?

A. Elimination
B. Nucleophilic substitution
C. Free radical substitution
D. Nucleophilic addition

Question 4: What is the correct product from CH₃CH₂Br + 2NH₃ (in ethanol, heated)?

A. CH₃CH₂CN
B. CH₃CH₂NH₂
C. CH₃CH₂OH
D. CH₃CH₂COOH

Question 5: What is the side product in the synthesis of a primary amine using excess ammonia?

A. HCl
B. NH₄⁺X⁻
C. H₂O
D. KOH

Question 6: Which compound contains a –C≡N group?

A. Amine
B. Hydroxynitrile
C. Alcohol
D. Ketone

Question 7: What reagent is used to convert a halogenoalkane into a nitrile?

A. NH₃
B. KOH (aq)
C. KCN
D. HCN

Question 8: What are the conditions for the conversion of a halogenoalkane to a nitrile?

A. Cold, dilute HCl
B. Reflux with KCN in ethanol
C. Room temperature with H₂SO₄
D. Reflux with NaOH in water

Question 9: What is the mechanism when a halogenoalkane reacts with CN⁻?

A. Electrophilic substitution
B. Nucleophilic addition
C. Nucleophilic substitution
D. Elimination

Question 10: What is the organic product from CH₃CH₂Br + KCN (in ethanol, reflux)?

A. CH₃CH₂NH₂
B. CH₃CH₂CN
C. CH₃CH₂OH
D. CH₃CH₂COOH

Question 11: Which species acts as the nucleophile in the formation of a nitrile?

A. NH₃
B. OH⁻
C. CN⁻
D. H⁺

Question 12: What is a hydroxynitrile?

A. A compound containing –OH and –C≡N
B. A compound with two –OH groups
C. An amide
D. A compound with an ester and amine group

Question 13: How is a hydroxynitrile formed from an aldehyde?

A. Reaction with NH₃ and heat
B. Reaction with HCN or KCN and heat
C. Reaction with Br₂ in ethanol
D. Reaction with NaOH and reflux

Question 14: Which of the following is a correct reagent pair for forming HCN in situ?

A. KCN and dilute HCl
B. NaOH and NH₃
C. H₂SO₄ and CH₃OH
D. HCl and Cl₂

Question 15: What type of mechanism occurs when HCN adds to an aldehyde?

A. Electrophilic substitution
B. Free radical addition
C. Nucleophilic addition
D. Nucleophilic substitution

Question 16: What is the product when CH₃CHO reacts with HCN?

A. CH₃CH(OH)CN
B. CH₃CH₂CN
C. CH₃CH₂OH
D. CH₃CH(OH)COOH

Question 17: What condition is required for forming hydroxynitriles from carbonyl compounds?

A. Heat with NaOH
B. Heat with KCN and dilute acid
C. Heat with concentrated H₂SO₄
D. UV light

Question 18: What functional groups are found in hydroxynitriles?

A. Amide and ester
B. Nitrile and hydroxyl
C. Alkene and alcohol
D. Ketone and ether

Question 19: Which of the following is formed when a nitrile undergoes acidic hydrolysis?

A. Alcohol
B. Amine
C. Carboxylic acid
D. Ketone

Question 20: What is produced when CH₃CH₂CN is hydrolysed with dilute HCl and heat?

A. CH₃CH₂OH
B. CH₃CH₂COOH
C. CH₃CH₂NH₂
D. CH₃CH₂CH₃

Question 21: What is produced when a nitrile is hydrolysed with NaOH followed by acidification?

A. Carboxylic acid
B. Amine
C. Alkene
D. Alcohol

Question 22: Which of the following would result from hydrolysing CH₃CH₂CN with NaOH followed by HCl?

A. Propan-1-ol
B. Propanamide
C. Propanoic acid
D. Propene

Question 23: What is the role of acidification after alkaline hydrolysis of nitriles?

A. Converts salt into alcohol
B. Converts amine to amide
C. Converts carboxylate salt into carboxylic acid
D. Oxidises nitrile

Question 24: Which compound can be made from both halogenoalkanes and aldehydes using cyanide?

A. Hydroxynitrile
B. Nitrile
C. Alcohol
D. Amine

Question 25: Which species is a product in the reaction between bromoethane and ammonia?

A. Ethanol
B. Ethylamine
C. Ethanoic acid
D. Ethanamide

Question 26: What is a correct condition for synthesising hydroxynitriles from ketones?

A. UV light and heat
B. NaCN and HCl, gentle warming
C. Dry HCl gas
D. Reflux with NaOH

Question 27: What is the correct IUPAC name for CH₃CH(OH)CN?

A. 2-hydroxyethanenitrile
B. 2-hydroxypropanenitrile
C. 1-hydroxyethanenitrile
D. 1-cyanoethanol

Question 28: Which atom in a carbonyl compound is attacked by CN⁻ during hydroxynitrile formation?

A. Hydrogen
B. Carbonyl carbon
C. Carbonyl oxygen
D. Alpha hydrogen

Question 29: What makes CN⁻ a good nucleophile?

A. Large size
B. Delocalised electrons
C. High electron density and negative charge
D. It is neutral and polar

Question 30: Which combination would convert CH₃CH₂Br into CH₃CH₂COOH?

A. NH₃ then acid
B. KCN then H₂O/HCl
C. HCN then NaOH
D. KOH then Br₂

Answer Key and Detailed Explanations – AS Level Chemistry: Chapter 19 Nitrogen Compounds Quiz

1. C. Primary amine
→ Ammonia reacts with halogenoalkane via nucleophilic substitution to form a primary amine.

2. D. Prevents substitution by water
→ Ethanol is used as the solvent to avoid hydrolysis and encourage substitution with ammonia.

3. B. Nucleophilic substitution
→ Ammonia (a nucleophile) substitutes the halogen in halogenoalkane.

4. B. CH₃CH₂NH₂
→ This is ethylamine, the primary amine formed from bromoethane and ammonia.

5. B. NH₄⁺X⁻
→ Ammonium halide is formed as the side product.

6. B. Hydroxynitrile
→ It contains both a hydroxyl (–OH) and a nitrile (–C≡N) group.

7. C. KCN
→ Potassium cyanide provides CN⁻ needed for nucleophilic substitution.

8. B. Reflux with KCN in ethanol
→ Standard conditions for converting halogenoalkanes to nitriles.

9. C. Nucleophilic substitution
→ CN⁻ substitutes the halide in a nucleophilic attack.

10. B. CH₃CH₂CN
→ This is propanenitrile, the product of substitution with CN⁻.

11. C. CN⁻
→ The cyanide ion is the nucleophile in the reaction.

12. A. A compound containing –OH and –C≡N
→ Hydroxynitriles (or cyanohydrins) have both functional groups.

13. B. Reaction with HCN or KCN and heat
→ Aldehydes and ketones react with HCN (or in situ CN⁻) to form hydroxynitriles.

14. A. KCN and dilute HCl
→ These react to form HCN in situ.

15. C. Nucleophilic addition
→ CN⁻ adds to the carbonyl carbon in a nucleophilic addition mechanism.

16. A. CH₃CH(OH)CN
→ This is 2-hydroxypropanenitrile, the hydroxynitrile formed from ethanal and HCN.

17. B. Heat with KCN and dilute acid
→ Heating helps form the hydroxynitrile efficiently.

18. B. Nitrile and hydroxyl
→ These are the two functional groups in a hydroxynitrile.

19. C. Carboxylic acid
→ Hydrolysis of a nitrile with acid yields a carboxylic acid.

20. B. CH₃CH₂COOH
→ This is propanoic acid, the hydrolysis product of propanenitrile.

21. A. Carboxylic acid
→ Base hydrolysis forms the salt; acidification yields the free acid.

22. C. Propanoic acid
→ CH₃CH₂CN → CH₃CH₂COOH by base hydrolysis then acidification.

23. C. Converts carboxylate salt into carboxylic acid
→ Final acidification step is necessary to regenerate the free acid.

24. B. Nitrile
→ Nitriles can be made from both aldehydes (via HCN) and halogenoalkanes (via KCN).

25. B. Ethylamine
→ CH₃CH₂Br + NH₃ forms ethylamine.

26. B. NaCN and HCl, gentle warming
→ Produces HCN in situ, which reacts with carbonyls to form hydroxynitriles.

27. B. 2-hydroxypropanenitrile
→ Correct IUPAC name for CH₃CH(OH)CN.

28. B. Carbonyl carbon
→ CN⁻ attacks the partially positive carbon of the C=O group.

29. C. High electron density and negative charge
→ CN⁻ is a strong nucleophile due to its negative charge and lone pair.

30. B. KCN then H₂O/HCl
→ Halogenoalkane → nitrile (via KCN) → carboxylic acid (via hydrolysis).