Question

Assertion :Bromine in Carbon Tetrachloride test is to distinguish between: Ethene gas & ethane gas. Reason: When this reaction occurs, molecular bromine is consumed, and its characteristic dark redbrown color disappears if bromine is not added in excess. The rapid disappearance of the bromine color is a positive test for unsaturation.

• A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
• B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
• C. Assertion is correct but Reason is incorrect
• D. Both Assertion and Reason are incorrect

Answer 1

The correct option is A Both Assertion and Reason are correct and Reason is the correct explanation for Assertion

Two common qualitative tests for unsaturation are the reaction of the compounds with bromide in carbon tetrachloride and with potassium permanganate. In both cases, a positive test is denoted by decolorization of the reagent.
Bromine in Carbon Tetrachloride Bromine will add to the carbon-carbon double bond of alkenes to produce dibromoalkanes and with alkynes to produce tetrabromoalkanes. When this reaction occurs, molecular bromine is consumed, and its characteristic dark red-brown color disappears if bromine is not added in excess. The rapid disappearance of the bromine color is a positive test for unsaturation.

Potassium Permanganate (the Baeyer Test) A second qualitative test for unsaturation, the Baeyer test, depends on the ability of potassium permanganate to oxidize the carbon-carbon double bond to give alkanediols or the carbon-carbon triple bond to give carboxylic acids.

only ethene gas gives both test and ethane doesn't give such tests.