CBSE Class 12 Chemistry Aldehydes Ketones Carboxylic Acids Questions Answers

Read and download free pdf of CBSE Class 12 Chemistry Aldehydes Ketones Carboxylic Acids Questions Answers. Students and teachers of Class 12 Chemistry can get free advanced study material, revision notes, sure shot questions and answers for Class 12 Chemistry prepared as per the latest syllabus and examination guidelines in your school. Standard 12 students should download this study material which will give them more knowledge for all chapters in Chemistry and all important topics which are scoring and can get you more marks. Students should also download free pdf of Chapter wise Notes for Class 12 Chemistry prepared by school teachers as per the latest NCERT, CBSE, KVS books and syllabus issued this year and also download free worksheets and question papers available here to get higher scores in school exams and tests, also click here for more Study Material for Class 12 Chemistry

CBSE Class 12 Chemistry Aldehydes Ketones Carboxylic Acids Questions Answers. There are many more useful educational material which the students can download in pdf format and use them for studies. Study material like concept maps, important and sure shot question banks, quick to learn flash cards, flow charts, mind maps, teacher notes, important formulas, past examinations question bank, important concepts taught by teachers. Students can download these useful educational material free and use them to get better marks in examinations.  Also refer to other worksheets for the same chapter and other subjects too. Use them for better understanding of the subjects.

ALDEHYDES,KETONES AND CARBOXYLIC ACIDS

SECTION-A 

1. Name one distinguishing test between aldehydes and ketones?

Ans. Aldehydes and ketones can be distinguished by Tollen’s test. Aldehydes give a silver mirror on reacting with Tollen’s reagent whereas ketones will not react.

2. Give reason why Formaldehyde does not undergo aldol condensation?

Ans. Formaldehyde does not have any α -hydrogen and therefore it cannot show aldol condensation.

3. Carboxylic acids have higher boiling points than alcohols of same no. of carbon atoms?

Ans. Carboxylic acids have more extensive association of molecules through intermolecular hydrogen bonding than alcohols.

4. Write IUPAC name .of CH3COCH2COCH3.

Ans.Pentane-2,4-dione.

5. What product is obtained when Ethyl benzene is oxidized with alkaline KMnO4?

Ans. Benzoic acid is formed.

6. Give chemical test to distinguish between acetaldehyde and benzaldehyde.

Ans. Acetaldehyde will respond to Iodoform test whereas benzaldehyde does not.

7. Write one chemical to distinguish between Formic acid and Acetic acid.

 Ans.Formic acid gives silver mirror when treated with Tollen,’s reagent whereas acetic acid does not.

8. Give two important uses of formalin.

Ans.Used as a preservative.

         Used for the preparation of Bakelite.

9. How is formalin and trioxane related to methanal?

Ans. Formalin is 40%aqeous solution of methanol whereas trioxane is trimer of methanal.

10. Complete the following reaction and give the name of the major product.

HCHO+ CH3MgX -----------------------------→ ?

Ans. HCHO +CH3MgX --------→-CH3CH2OH + Mg(OH)X

CH3CH2OH- Ethanol

11. Draw the structural formula of Hex-2-en4-yn-oic acid.

Ans. CH3-C≡C-CH=CHCOOH

12. Arrange the following in the increasing order of acidic character.

HCOOH, ClCH2COOH, CF3COOH, Cl3CCOOH

Ans. CF3COOH>CCl3COOH>ClCH2COOH>HCOOH

13. Complete the reaction:-

RCONH2+4NaOH+Br2 --------→

Ans.RCONH2+4NaOH+Br2-------→ RNH2+ 2NaBr+ Na2CO3+2H2O.

14. Give one chemical test to distinguish between Phenol and benzoic acid.

Ans. On treatment with neutral FeCl3 solution Phenol gives a violet color whereas Benzoic acid does not.

15. Most of the aromatic acids are solids while acetic acids and others of this series are liquids. Why?

Ans. Aromatic acids have higher molecular weights. Therefore more Vander Waal’s force of attraction as compared to aliphatic acids and hence they are solids. 

SECTION –B 

1. Would you expect benzaldehyde to be more or less reactive in nucleophilic addition reaction

than Propanal? Explain your answer.

Ans. The carbon atom of the carbonyl group of benzaldehyde is less electrophilic than carbon atom of the carbonyl group present in propanal. The polarity of the carbonyl group is reduced in benzaldehyde due to resonance and hence is less reactive.

2. Describe the Trans esterification reaction giving an example.

Ans. When an ester reacts with alcohol to form another ester and another alcohol, the process is called trans-esterification.

CH3COOC2H5 +CH3OH ----------→ CH3COOC2H5 + C2H5OH

3. Explain Hell- Volhard –Zelinsky reaction with an example.

Ans. Carboxylic acids having an a α hydrogen atom are halogenated at the α position on treatment with chlorine or bromine in the presence of small amount of red phosphorous to give α- halo carboxylic acids

                              (i)X2/P (Red)

RCH2COOH --------------→RCH(X) COOH.

                             (ii) H2O/H+

4. Give simple chemical tests to distinguish between:-

(i) Pentan-2-one and Pentane-3-one

(ii) Ethanal and propanal

Ans. (i) Pentan-2-one gives Iodoform test on treatment with I2/NaOHwhere as Pentane -3-one does not.

(ii)Ethanal gives Iodoform test whereas Propanal does not.

5. Although Phenoxide ion has more number of resonating structures than Carboxylate ion, Carboxylic

acids are more acidic than Phenol .Why?

Ans. In carboxylate ion (-)ve charge is delocalized over two oxygen atoms whereas in phenoxide ion (-)ve charge is delocalized over one oxygen atom .Therefore carboxylate ion is more stable than phenoxide ion .That is why Carboxylic acids are more acidic than Phenol.

6. Why is there a large difference in the boiling points of but anal and butan-1-ol?

Ans:-Butan-1-ol has higher boiling point due to intermolecular hydrogen bonding 

Please click the link below to download CBSE Class 12 Chemistry Aldehydes Ketones Carboxylic Acids Questions Answers.

Tags: 

 


Click to View or Download pdf file
Click for more Chemistry Study Material

Latest NCERT & CBSE News

Read the latest news and announcements from NCERT and CBSE below. Important updates relating to your studies which will help you to keep yourself updated with latest happenings in school level education. Keep yourself updated with all latest news and also read articles from teachers which will help you to improve your studies, increase motivation level and promote faster learning

FAQs on Policy for Tabulation of Marks for Class 10 Board Exams

ON POLICY Question.1 How CBSE will declare the result of Class-X? Answer. Results of Class X Board will be declared on the basis of an objective criterion developed by the Board vide Notification no.CBSE/CE/2021 dated 01.05.2021. Question.2. If any candidate is not...

Time management for CBSE students

The first thing to learn about Time Management is that time is theoretical so you can’t really manage it. What you do when you get into time management, is that you manage yourself. You decide what has to be done, when it must be done and how to do it in the stipulated...

CBSE Assessment Framework

The Central Board of Secondary Education (CBSE) today, announced a suggested competency-based assessment framework to strengthen India’s existing school education system for secondary level (classes 6-10) and improve the overall learning outcomes of students across...

Class 10 Boards Cancelled Class 12 postponed

Looking to the present situation of the pandemic and school closures, and also taking in account the safety and well-being of the students, it is decided as follows:   1. The Board Exams for Class XIIth to be held from May 4th to June, 14th, 2021 are hereby postponed....

ICSE Board Exams Cancelled

The ICSE (Class X) 2021 Examination: Given the present worsening situation of the Covid- 19 Pandemic in the country, the CISCE has decided to CANCEL the ICSE (Class X) 2021 Examination. The options given in the earlier Circular dated 16th April 2021, now stands...

×
Studies Today