Question

Assertion : Change in colour of acidic solution of potassium dichromate by breath is used to test drunk drivers. 

Reason : Change in colour is due to the complexation of alcohol with potassium dichromate.

(a) Both A and R are true and R is the correct explanation of A

(b) Both A and R are true but R is not correct explanation of A

(c) A is true but R is false

(d) A and R are false

Answer 1

The correct option is (c) A is true but R is false.

Explanation:

Change in colour is due to the oxidation of alcohol with potassium dichromate. K₂Cr₂O₇ in presence of dilute H₂SO₄ acts as an oxidising agent. It is converted into chromic sulphate which is green in colour.