Tag: Kendriya Vidyalaya Students

Cannizzaro’s Reaction

The reaction in which the carbonyl compound (having no alpha hydrogen) is treated with base (NaOH or KOH) to produce alcohol and Carboxylate ion is called Cannizzaro’s reaction.

The cannizzro,s reaction is given by the aldehydes which has no alpha hydrogen.
The aldehyde oxidizes to carboxylate ion and reduced to alcohol.
Cannizzaro’s reaction is disproportionation reaction.
The reaction in which same molecule oxidizes and reduced simultaneously is called disproportionation reaction..

Question:- Which compounds gives Cannizzaro’s reaction out of the following compounds and why?

A

B

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C.

D.

Answer:-Compounds A and C gives Cannizzaro’s reaction because they have absence of alpha hydrogen atom.

Molecular Orbital Diagram of Oxygen 11th Standard

Question:-Explain the paramagnetic nature of oxygen and calculate bond order by drawing molecular orbital orbital diagram and molecular orbital electronic configuration.

Diazotization Reaction

In diazotization Reaction, The aniline is treated with nitrous acid ( a mixture of sodium nitrite and hydrochloric acid) at temperature 00 to 50 Celsius ( 273 K to 278 K ) to produce diazonium chloride.

Nitrous acid is produce in the reaction mixture by treating NaNO2 with HCl

NaNO2 + HCl  —> HNO2 + NaCl

Diazonium salt is highly unstable and can explode at little higher temperature therefore it is prepared at lower temperature (00 to 50 Celsius).

Diazonium salt can not be separated and product mixture is used for further reaction because diazonium salt is highly unstable and explode on distillation (on heating).

Diazonium salt is very much important in organic synthesis as for preparation of large number of organic compounds, it is precursor (Reactant).

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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) CH3COCH3 and 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 CH3CH2COCH2CH3      The 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