Question

Lime water does not help in distinguishing co2 and so2 whereas acidified potassium dichromate solution helps give reason

Answer 1

The mixture of carbon dioxide and sulphur dioxide is passed into acidified potassium dichromate solution. Sulphur dioxide reacts with acidified potassium dichromate solution to form green coloured solution. Potassium dichromate is reduced to chromic sulphate. When carbon reacts with potassium the solution turns reddish pink.Carbon dioxide is not affected by potassium dichromate. Hence, it turns lime water milky.

K

2

Cr

2

O

7

+3SO

2

+H

2

SO

4

→K

2

SO

4

+Cr

2

(SO

4

)

3

+H

2

O