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Assertion : Change in colour of the acid...

Assertion : Change in colour of the acidic solution of breath is used as a test for drunken driver.
Reason : Change in colour is due to complexation of alcohol with potassium dichromate.

A

If both assertion and reason are correct and reason is correct explanation for assertion.

B

If both assertion and reason are correct but reason is not correct not correct explanation for assertion.

C

If assertion is correct but reason is incorrect.

D

If both assertion and reason are incorrect.

Text Solution

Verified by Experts

The correct Answer is:
C
(c) Correct reason. Acidified `K_(2)Cr_(2)O_(7)` is an oxidising agent and oxideses primary alcohol (ethyl alcohol) to acid (acetic acid). At the same time, it is reduced to chromium sulphate (green).
`underset("(orange)")underset()(K_(2)Cr_(2)O_(7))+4H_(2)SO_(4)rarrK_(2)SO_(4)+underset("(green)")underset()(Cr_(2)(SO_(4))_(3))+4H_(2)O+3(O)`
If the colour of orange solution changes to green, this means that breath has alcohol or the driver has consumed alcohol. If the colour re1nains unchanged, this means that breath has no alcohol.
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