Question

Compound 'A' on chlorination gives compound 'B', compound 'B' reacts with alc. KOH gives gas 'C', which decolourizes Baeyer's reagent and ozonolysis of compound 'C' gives only HCHO compound. Then compound 'A' is:

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Answer 1

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Compound A is calcium oxide (commonly known as quick lime). It has the chemical formula CaO. Compound B is calcium hydroxide, commonly known as slaked lime. It has the chemical formula Ca(OH)2. Compound C is calcium carbonate. It has the chemical formula CaCO3. Following are the involved chemical reactions:

1) Reaction of calcium oxide and water

CaO + H2O → Ca(OH)2

2) Reaction of calcium hydroxide and carbon dioxide

Ca(OH)2 + CO2 → CaCO3 + H2O

Answer 2

The compound A is ethylene C  

2

​  

H  

6

​  

.

It on chlorination gives compound B which is ethyl chloride.

A

C  

2

​  

H  

6

​  

 

​  

 

chlorination

​  

 

B

C  

2

​  

H  

5

​  

Cl

​  

 

On dehydrohalogenation with alc. KOH, ethyl chloride gives ethylene (gas C).

B

C  

2

​  

H  

5

​  

Cl

​  

→  

C

CH  

2

​  

=CH  

2

​  

 

​  

 

Ethylene decolourizes Baeyer reagent.

C  

2

​  

H  

4

​  

+H  

2

​  

O+[O]→CH  

2

​  

OH−CH  

2

​  

OH

Ozonolysis of ethylene gives formaldehyde.

CH  

2

​  

=CH  

2

​  

 

Ozonolysis

​  

2HCHO.