Question

hexane and hexene are hydrocarbons.they are highly flammable liquids and have irritating vapours.a student adds a few drops of bromine water to a small volume of hexane in a test tube,then shakes the mixture,she repent the test using hexene


a.explain how the results of the student tests distinguish between hexane and hexene

b.give one suitable safety precaution,and explain your answer

Answer 1

Hexene will be positive towards the bromine water test whereas, hexane will show no results.

• In the qualitative analysis of organic compounds, bromine water is used as a reagent to distinguish between saturated and unsaturated compounds.
• When unsaturated compounds are exposed to bromine water, the brown colour of the bromine water disappears.
• Hence, owing to the unsaturation present in hexene, it will decolourize the bromine water.
• Since hexane is a saturated compound, it will not produce any colour change.
• SAFETY PRECAUTION : Avoid inhalation of bromine as it can have adverse health effects like, headache and nausea.