12th Chemistry - Book Back Answers - Unit 12 Carbonyl Compounds And Carboxylic Acids- English Medium Guides

  

 

Plus Two / 12th Chemistry - Book Back Answers - Unit 12 - English Medium

Tamil Nadu Board 12th Standard Chemistry - Unit 12: Book Back Answers and Solutions

    This post covers the book back answers and solutions for Unit 12 from the Tamil Nadu State Board 12th Standard Chemistry textbook. These detailed answers have been carefully prepared by our expert teachers at KalviTips.com.

    We have explained each answer in a simple, easy-to-understand format, highlighting important points step by step under the relevant subtopics. Students are advised to read and memorize these subtopics thoroughly. Once you understand the main concepts, you’ll be able to connect other related points with real-life examples and confidently present them in your tests and exams.

    By going through this material, you’ll gain a strong understanding of Unit 12 along with the corresponding book back questions and answers (PDF format).

Question Types Covered:

• 1 Mark Questions: Choose the correct answer, Fill in the blanks, Identify the correct statement, Match the following 
• 2 Mark Questions: Answer briefly 
• 3, 4, and 5 Mark Questions: Answer in detail

All answers are presented in a clear and student-friendly manner, focusing on key points to help you score full marks.

All the best, Class 12 students! Prepare well and aim for top scores. Thank you!

Unit 12 - Carbonyl Compounds And Carboxylic Acids

I. Multiple Choice Questions

1. The correct structure of the product ‘A’ formed in the reaction 

 

a) 

b) 

c) 

d) 

Answer Key:

 

2. The formation of cyanohydrin from acetone is an example of

a) nucleophilic substitution

b) electrophilic substitution

c) electrophilic addition

d) Nucleophilic addition

Answer Key:

d) Nucleophilic addition

  

3. Reaction of acetone with one of the following reagents involves nucleophilic addition followed by elimination of water. The reagent is

a) Grignard reagent

b) Sn / HCl

c) hydrazine in presence of slightly acidic solution

d) hydrocyanic acid

Answer Key:

c) hydrazine in presence of slightly acidic solution 

  

4. In the following reaction, 

$\mathbf{H}\mathbf{C}\mathbf{\equiv }\mathbf{C}\mathbf{H}\mathbf{ }\underset{\mathbf{H}\mathbf{g}\mathbf{S}{\mathbf{O}}_{\mathbf{4}}}{\overset{{\mathbf{H}}_{\mathbf{2}}\mathbf{S}{\mathbf{O}}_{\mathbf{4}}}{\mathbf{\to }}}$ X Product ‘X’ will not give

a) Tollen’s test

b) Victor meyer test

c) Iodoform test

d) Fehling solution test

Answer Key:

b) Victor meyer test 

 

5. $\mathbf{C}{\mathbf{H}}_{\mathbf{2}}\mathbf{\equiv }{\mathbf{CH}}_{\mathbf{2}}\underset{\mathbf{i}\mathbf{i}\mathbf{)}\mathbf{ }\mathbf{Z}\mathbf{n}\mathbf{/}{\mathbf{H}}_{\mathbf{2}}\mathbf{O}}{\overset{\mathbf{i}\mathbf{)}\mathbf{ }{\mathbf{O}}_{\mathbf{3}}}{\mathbf{\to }}}\mathbf{X}\mathbf{ }\stackrel{\mathbf{N}{\mathbf{H}}_{\mathbf{3}}}{\mathbf{\to }}$ Y ‘Y’ is

a) Formaldelyde

b) di acetone ammonia

c) hexamethylene tetraamine

d) oxime

Answer Key:

c) hexamethylene tetraamine 

  

6. Predict the product Z in the following series of reactions

Ethanoic acid  $\stackrel{\mathbf{P}\mathbf{C}{\mathbf{l}}_{\mathbf{5}}}{\mathbf{\to }}\mathbf{X}\underset{\mathbf{Z}\mathbf{n}\mathbf{h}\mathbf{y}\mathbf{d}\mathbf{r}\mathbf{o}\mathbf{u}\mathbf{s}\mathbf{ }\mathbf{A}\mathbf{l}\mathbf{C}{\mathbf{l}}_{\mathbf{3}}}{\overset{{\mathbf{C}}_{\mathbf{6}}{\mathbf{H}}_{\mathbf{5}}}{\mathbf{\to }}}\mathbf{Y}\underset{\mathbf{i}\mathbf{i}\mathbf{)}\mathbf{ }{\mathbf{H}}_{\mathbf{3}}{\mathbf{O}}^{\mathbf{+}}}{\overset{\mathbf{i}\mathbf{)}\mathbf{ }\mathbf{C}{\mathbf{H}}_{\mathbf{3}}\mathbf{M}\mathbf{g}\mathbf{B}\mathbf{r}}{\mathbf{\to }}}$

a) (CH₃)₂C(OH)C₆H₅

b) CH₃CH(OH)C₆H₅

c) CH₃CH(OH)CH₂ – CH₃

_d) 

Answer Key:

a) (CH₃)₂C(OH)C₆H₅

  

7. Assertion: 2, 2 – dimethyl propanoic acid does not give HVZ reaction.

Reason: 2 – 2, dimethyl propanoic acid does not have _ - hydrogen atom

a) if both assertion and reason are true and reason is the correct explanation of assertion.

b) if both assertion and reason are true but reason is not the correct explanation of

assertion.

c) assertion is true but reason is false

d) both assertion and reason are false.

Answer Key:

a) if both assertion and reason are true and reason is the correct explanation of assertion.

  

8. Which of the following represents the correct order of acidity in the given compounds

a) FCH₂COOH > CH₃COOH > BrCH₂COOH > ClCH₂COOH

b) FCH₂COOH > ClCH₂COOH > BrCH₂COOH > CH₃COOH

c) CH₃COOH > ClCH₂COOH > FCH₂COOH > Br-CH₂COOH

d) ClCH₂COOH > CH₃COOH > BrCH₂COOH > ICH₂COOH

Answer Key:

b) FCH₂COOH > ClCH₂COOH > BrCH₂COOH > CH₃COOH

  

9. Benzoic acid  $\underset{\mathbf{i}\mathbf{i}\mathbf{)}\mathbf{ }\mathbf{△}}{\overset{\mathbf{i}\mathbf{)}\mathbf{ }\mathbf{N}{\mathbf{H}}_{\mathbf{3}}}{\mathbf{\to }}}\mathbf{A}\stackrel{\mathbf{N}\mathbf{a}\mathbf{O}\mathbf{B}\mathbf{r}}{\mathbf{\to }}\mathbf{B}\stackrel{\mathbf{N}\mathbf{a}\mathbf{N}{\mathbf{O}}_{\mathbf{2}}\mathbf{/}\mathbf{H}\mathbf{C}\mathbf{l}}{\mathbf{\to }}\mathbf{C}$ C ‘C’ is

a) anilinium chloride

b) O – nitro aniline

c) benzene diazonium chloride

d) m – nitro benzoic acid

Answer Key:

c) benzene diazonium chloride 

  

10. Ethanoic acid $\stackrel{\mathbf{P}\mathbf{/}\mathbf{B}{\mathbf{r}}_{\mathbf{2}}}{\mathbf{\to }}$ 2 – bromoethanoic acid. This reaction is called

a) Finkelstein reaction

b) Haloform reaction

c) Hell – Volhard – Zelinsky reaction

d) none of these

Answer Key:

c) Hell – Volhard – Zelinsky reaction 

  

11. $\mathbf{C}{\mathbf{H}}_{\mathbf{3}}\mathbf{B}\mathbf{r}\stackrel{\mathbf{K}\mathbf{C}\mathbf{N}}{\mathbf{\to }}\mathbf{\left(}\mathbf{A}\mathbf{\right)}\stackrel{{\mathbf{H}}_{\mathbf{3}}{\mathbf{O}}^{\mathbf{+}}}{\mathbf{\to }}\mathbf{\left(}\mathbf{B}\mathbf{\right)}\stackrel{\mathbf{P}\mathbf{C}{\mathbf{l}}_{\mathbf{5}}}{\mathbf{\to }}\mathbf{\left(}\mathbf{C}\mathbf{\right)}$ product (C) is

a) acetylchloride

b) chloro acetic acid

c) $\mathbf{\alpha }$ - chlorocyano ethanoic acid

d) none of these

Answer Key:

a) acetylchloride

  

12. Which one of the following reduces tollens reagent

a) formic acid

b) acetic acid

c) benzophenone

d) none of these

Answer Key:

a) formic acid

  

13. 

 B ‘B’ is

a) 

b) 

c) 

d) 

Answer Key:

 

 

 14. The IUPAC name of 

a) but – 3- enoicacid

b) but – 1- ene-4-oicacid

c) but – 2- ene-1-oic acid

d) but -3-ene-1-oicacid

Answer Key:

a) but – 3- enoicacid 

  

15. Identify the product formed in the reaction 

a) 

b) 

c) 

d) 

Answer Key:

 16. In which case chiral carbon is not generated by reaction with HCN

a) 

b) 

c) 

d) 

Answer Key:

 17. Assertion : p – N, N – dimethyl aminobenzaldehyde undergoes benzoin condensation

Reason : The aldehydic (-CHO) group is meta directing

a) if both assertion and reason are true and reason is the correct explanation of assertion.

b) if both assertion and reason are true but reason is not the correct explanation of assertion.

c) assertion is true but reason is false 

d) both assertion and reason are false.

Answer Key:

b) if both assertion and reason are true but reason is not the correct explanation of assertion.

  

18. Which one of the following reaction is an example of disproportionation reaction

a) Aldol condensation

b) cannizaro reaction

c) Benzoin condensation

d) none of these

Answer Key:

b) cannizaro reaction

  

19. Which one of the following undergoes reaction with 50% sodium hydroxide solution to give the corresponding alcohol and acid

a) Phenylmethanal

b) ethanal

c) ethanol

d) methanol

Answer Key:

a) Phenylmethanal

  

20. The reagent used to distinguish between acetaldehyde and benzaldehyde is

a) Tollens reagent

b) Fehling’s solution

c) 2, 4 – dinitrophenyl hydrazine

d) semicarbazide

Answer Key:

b) Fehling’s solution

  

 21. Phenyl methanal is reacted with concentrated NaOH to give two products X and Y. X reacts with metallic sodium to liberate hydrogen X and Y are

a) sodiumbenzoate and phenol

b) Sodium benzoate and phenyl methanol

c) phenyl methanol and sodium benzoate

d) none of these

Answer Key:

c) phenyl methanol and sodium benzoate

  

22. In which of the following reactions new carbon – carbon bond is not formed?

a) Aldol condensation

b) Friedel craft reaction

c) Kolbe’s reaction

d) Wolf kishner reduction

Answer Key:

d) Wolf kishner reduction

  

23. An alkene “A” on reaction with O₃ and Zn – H₂O gives propanone and ethanal in equimolar ratio. Addition of HCl to alkene “A” gives “B” as the major product. The structure of product “B” is

a) $\mathbf{C}\mathbf{l}\mathbf{-}\mathbf{C}{\mathbf{H}}_{\mathbf{2}}\mathbf{-}\mathbf{C}{\mathbf{H}}_{\mathbf{2}}\mathbf{-}\underset{\underset{\mathbf{C}{\mathbf{H}}_{\mathbf{3}}}{\mathbf{|}}}{\overset{\underset{\mathbf{|}}{\mathbf{C}{\mathbf{H}}_{\mathbf{3}}}}{\mathbf{C}\mathbf{H}}}$

b) $|{\mathbf{H}}_{\mathbf{3}}\mathbf{C}\mathbf{-}\mathbf{ }{\mathbf{CH}}_{\mathbf{2}}\mathbf{-}\stackrel{\stackrel{\mathbf{C}{\mathbf{H}}_{\mathbf{2}}\mathbf{C}\mathbf{l}}{\mathbf{|}}}{\mathbf{C}\mathbf{H}}\mathbf{-}\mathbf{C}{\mathbf{H}}_{\mathbf{3}}$

c) ${\mathbf{H}}_{\mathbf{3}}\mathbf{C}\mathbf{-}\mathbf{C}{\mathbf{H}}_{\mathbf{2}}\mathbf{-}\underset{\underset{\mathbf{C}\mathbf{l}}{\mathbf{|}}}{\overset{\stackrel{\mathbf{C}{\mathbf{H}}_{\mathbf{3}}}{\mathbf{|}}}{\mathbf{C}}}\mathbf{-}\mathbf{ }\mathbf{C}{\mathbf{H}}_{\mathbf{3}}$

d) ${\mathbf{H}}_{\mathbf{3}}\mathbf{C}\mathbf{-}\mathbf{C}\mathbf{H}\mathbf{-}\underset{\underset{\mathbf{C}\mathbf{l}}{\mathbf{|}}}{\overset{\stackrel{\mathbf{C}{\mathbf{H}}_{\mathbf{3}}}{\mathbf{|}}}{\mathbf{C}\mathbf{H}}}$

Answer Key:

c) ${\mathbf{H}}_{\mathbf{3}}\mathbf{C}\mathbf{-}\mathbf{C}{\mathbf{H}}_{\mathbf{2}}\mathbf{-}\underset{\underset{\mathbf{C}\mathbf{l}}{\mathbf{|}}}{\overset{\stackrel{\mathbf{C}{\mathbf{H}}_{\mathbf{3}}}{\mathbf{|}}}{\mathbf{C}}}\mathbf{-}\mathbf{ }\mathbf{C}{\mathbf{H}}_{\mathbf{3}}$

${\mathbf{ }}_{}$ 

24. Carboxylic acids have higher boiling points than aldehydes, ketones and even alcohols of comparable molecular mass. It is due to their

a) more extensive association of carboxylic acid via van der Waals force of attraction

b) formation of carboxylate ion

c) formation of intramolecular H-bonding

d) formation of intermolecular H – bonding

Answer Key:

d) formation of intermolecular H – bonding 

 

II. Short Answer Questions.

12th Chemistry

III. Long Answer Questions. 

12th Chemistry

IV. Exercise.   

12th Chemistry