Question

Reagent used to test unsaturation in alkene :

1) ammonical Cu₂Cl₂
2) ammonical AgNO₃ solution
3) solution of Br₂ in CCl₄
4) conc. H₂SO₄

Answer 1

3) Solution of Br2 in CCl4
_______________
Reaction Involved :
CH2=CH2 + Br2 | CCl4 ---------> CH2Br-CH2Br
The reddish Orange color of Bromine solution in CCl4 decolorized . Thus serves as a test to detect unsaturation .

Answer 2

C) is the correct answer.An unknown sample is treated with a small amount of elemental bromine in an organic solvent, being as dichloromethane or carbon tetrachloride. Presence of unsaturation and/or phenol in the sample is shown by disappearance of the deep brown coloration of bromine when it has reacted with the unknown sample. CH2=CH2 + Br2 >>>>Ch2Br -ch2br