Question

What is the test used to identify presence of alkene?

Answer 1

alkenes have carbon-carbon bond, they will react with bromine colour is reddish brown to colourless this test is commonly used to find out weather alkenes are present

Answer 2

___________________________________________________

By adding  cold dilute Baeyer's reagnant

More about Baeyer's Reagnant.

• Baeyer's reagnant is cold dilute

• It is an oxidising agent.

If this mixture is added to an unsaturated compounds such as alkenes or alkanes then :

• Purple colour of  changes .

• It is first converted to a green compound   which is unstable in alkaline medium.

• This again changes to brown  

• The supernatant liquid gets decolourised.

However saturated compounds do not respond to the above test.

In simple words........... your answer is :

In order to test unsaturation first add cold dilute Baeyer's reagnant.

If the reagnant decolorises from purple to colourless then the compound is unsaturated

Otherwise if the reaction does not occur , then it is a saturated compound.

__________________________________________