Both propane and propene react with bromine. State two ways in which these two hydrocarbons can be distinguished in their reaction with bromine
I'll give you a hint for one. Br2 bubbled into propene simply adds to the double bond and the Br2 solution turns colorless. Added to propane, Br2 gives HBr as one of the products.
To distinguish between propane and propene in their reaction with bromine, you can utilize two main methods:
1. Bromine Water Test:
- Take a small sample of the hydrocarbon and add it to a test tube containing bromine water (aqueous solution of bromine).
- If the hydrocarbon is propene, it will undergo an addition reaction with bromine, resulting in the decolorization or fading of the orange-brown color of bromine water due to the formation of colorless 1,2-dibromo propane.
- However, if the hydrocarbon is propane, it will not react with bromine water, and the orange-brown color will remain.
2. Bromine Addition Reaction:
- Take a sample of the hydrocarbon and add a few drops of liquid bromine (Br2) to it.
- If the hydrocarbon is propene, it will readily undergo an addition reaction with bromine, forming 1,2-dibromo propene. This reaction can be identified by observing a decolorization or fading of the reddish-brown color of bromine due to the formation of a dark-colored bromoalkane product.
- On the other hand, if the hydrocarbon is propane, it will not react with bromine under normal conditions, and the reddish-brown color of bromine will remain unchanged.
By performing these two tests, you can distinguish between propane and propene based on their reactions with bromine.