Explanation;
Bromine test is done to distinguish between the unsaturated hydrocarbons from saturated hydrocarbons.
When we add bromine water to an unsaturated hydrocarbon ,bromine atoms get attached to the carbons with double bond in between. This reaction between bromine water and unsaturated hydrocarbon results in de-colorization of bromine water color from red to colorless.
When bromine water is added to hexane no color change will be observed.
no reaction
When bromine water is added to 2-hexene color change will be observed.
Metals such as iron, zinc, lead, copper, etc., are in the middle of the reactivity series. These are moderately reactive metals and are usually present as sulphides or carbonates. A metal is obtained from its ore by the processes of reduction or by electrolysis.