Question

What happens when you put bromine water with an alkene or an alkane?

Answer 1

Would not the olefin decolourize the bromine water to give the halohydrin...?

Explanation:

`R-CH=CH_2 +underbrace(Br_2)_"orange brown"stackrel(H_2O)rarrunderbrace(RCH(OH)CH_2Br)_"colourless"+HBr`

When you do these organic spot tests, it is always a good idea to do a pretest on AUTHENTIC samples, i.e. here a KNOWN olefin, and bromine water, so that you know the results of a positive test...

On the other hand, an alkane should be inert towards bromine water... of course a source of UV light (i.e. sunlight) should promote the radical reaction...