Aldehydes Ketones and Ethers(12 Std):- Important and conceptual questions

Aldehydes Ketones and Ethers:- Important and conceptual questions

Answers are given in the end-

1. Why does carbonyl compounds give Nucleophylic reaction?

2. Arrange the following carbonyl compounds in increasing order of their reactivities towards nucleophylic addition reaction.

CH₃CHO, HCHO, CH₃COCH₃

3.Which of the following compounds give iodoform reaction and why?

CH₃CHO, HCHO, CH₃CH₂COCH₂CH₃

4 Which of the following compounds give cannizaro,s reaction and why?

CH₃CHO, HCHO, CH₃CH₂COCH₂CH₃

5. Which of the following compounds give aldol condensation reaction and why?

CH₃CHO, HCHO, CH₃CH₂COCH₂CH₃

6. How many compounds are formed in the cross aldol condensation of

A) CH₃CHO, CH₃COCH₃

B) Ph-CHO and CH₃CHO

C) Ph-CO-Ph and CH₃CHO

D) CH₃COCH₃and CH₃CH₂COCH₂CH₃

E) Ph-CHO and Ph-CO-Ph

7.What are the disproportion reaction. Give example.

Answer-

1. Nucleophylic reaction reaction occure due to presence of partial positive charge on carbonyl carbon and addition reaction occure due to presence of double bond.

2. CH₃COCH₃< CH₃CHO < HCHO

3. CH₃CHO, The compounds have three alpha hydrogen atoms to carbonyl groups gives iodoform reaction.

4. HCHO, The compounds have no any alpha hydrogen atoms to carbonyl groups gives cannizaro,s reaction.

5. CH₃CHO and CH₃CH₂COCH₂CH₃The compounds have atleast one alpha hydrogen atoms to carbonyl groups gives aldol condensation reaction.

6. A) Four aldol products

B) Two aldol products

C)Two aldol products

D) Four aldol products

E) No aldol products

7. The reaction in which same species is oxidized and reduced simultaneously.

Example is cannizaro,s reaction in which carbonyl compounds having no alpha hydrogen is oxidized in carboxylate ion and reduced to alcohol.

Ph-CHO + KOH à Ph-COO^– + Ph-CH₂-OH

Important Distinguish test of Function Groups (12 Board Exam) Click Here

Answers are given in the end-

1. How will you distinguish butanol, butan-2-ol and 2-Methylbutan-2-ol

2. How will you distinguish aniline and phenol?

3.How will you distinguish phenol and ethanol?

4.How will you distinguish ethanamine and N-Methyl methanine.

5.How will you distinguish Propanamine and N,N-Dimethylethanamine.

6.How will you distinguish Propanamine, N-Methyethanamine and N,N-Dimethylmethanamine.

7. How will you distinguish Ethanol and Ethanoic acid.

8.How will you distinguish Methanal and Ethanal?

9.How will you distinguish Propanal and Propanol.

10.How will you distinguish Propanol and Ethanol?

11.How will you distinguish Choloromethane and Chlorobenzene.

Answer-
1.When Licas reagent (ZnCl2 + HCl ) is added than turbidity appears immediately in Methylbutan-2-ol ( tertiary alcohol), turbidity appears after 5 minutes in butan-2-ol ( Secondary alcohol) and no turbidity appears in butanol ( Primary alcohol).

2.Phenol gives violet colour with neutral FeCl3 while aniline does not.

3.Ethanol gives red colour with ceric ammonium nitrate while phenol does not.

4.Ethanamine reacts with benzenesulphonyl chloride( Hinesburg’s Reagent) which is soluble in dilute solution of NaOH, whereas N-Methyl methanine reacts but insoluble in dilute solution of NaOH.

5.Propanamine reacts with benzenesulphonyl chloride ( Hinesburg’s Reagent) which is soluble in dilute solution of NaOH, whereas N,N-Dimethylethanamine does not react.

6.Propanamine reacts with benzenesulphonyl chloride ( Hinesburg’s Reagent) which is soluble in dilute solution of NaOH whereas N-Methyl ethanine reacts but insoluble in dilute solution of NaOH whereas N,N-Dimethylethanamine does not react.

7.Ethanol gives red colour with ceric ammonium nitrate while Ethanoic acid does not.
Or Ethanol gives frutty smell of esters with ethanoic acid and few drops of conc. H2SO4 whereas ethanoic acid does not. (Note- This is ester test)

8.Ethanal gives yellow ppt with a mixture of NaOH and I₂ while methanol does not ( Iodoform,s Test)

9.Propanal gives silver mirror or black ppt with Tollen,s reagent( AgNO3 + NH4OH) while Propanol does not.
Or Propanal gives red ppt with mixture of Fehling,s solution A ( solution of CuSO4) and B ( solution of sodium potassium tartarate and NaOH) while Propanol does not.
( Note- Aldehydes gives Tollens test and Fehling,s solution test while ketones does not.)

10.Ethanol gives yellow ppt with a mixture of NaOH and I₂while propanol does not (Note-This is Iodoform,s Test given by compounds having three alpha hydrogen to carbonyl group or three beta hydrogen to alcoholic group)

11.Choloromethane gives white precipitate with AgNO3 but Chlorobenzene does not.

Biomolecules (XII Std)-Important and conceptual Questions

Answer are given in the end–

Questions useful in Board Examination.

1.What is basic unit of carbohydrates?

2.What is basic unit of protein or polypeptide?

3.What is the non reducing sugar and what is cause of it?

4.What do you mean primary structure of protein ?

5. What do you mean secondary structure of protein ?

6.What do you mean tertiary structure of protein ?

7.What is native structure of protein?

8.What is zwitter ion.

9.Which vitamins are fat soluble?

10.What is importance of primary structure of protein?

Answers-

1.Glycosidic Linkages

2.Peptide bond

3.The sugar which reduces Tollen,s reagents or Fehling,s solution is called reducing sugar. It is because their carbonyl functions are not free.

4.The specific sequence of amino acid in protein is called primary structure of protein.

5.Alpha halix or beta pleated sheet are secondary structure of protein which is stabilized by hydrogen bonds. alpha helix is a helical structure whereas beta pleated sheet is formed by placing primary structure sidewise.

6.Tertiary structure of protein is formed by overlapping and folding of primary and secondary structure of over each other. Tertiary structure is stabilized by following bonds-
1) Hydrogen bond formed between -NH₂ group and C=O group of different part of polypeptide chain.
2) Ionic bond formed between -NH₃⁺ and COO^– groups of different part of polypeptide chain.
3) Disulphide bond -S-S- between different part of polypeptide chain.
4) Hydrophobic bond is not actual type of bond but it is a condition in which nonpolar hydrophobic chains moves inside the protein.

7. The original and active shape of protein at particular pH range and temperature range is called native state of Protein.

8.The bipolar ion of amino acid is called zwitter ion.

9.Vitamins A , D , E and K are fat soluble.

10.The change only in one amino acid in polypeptide chain changes property also. Example-In sickle cell anemia is an inherited disease which affect red blood cell and change it into sickle shaped. It is due to change in only one amino acid i.e. glutamic acid by valine in the polypeptide chain making hemoglobin.