British Sign Language Glossaries of Curriculum Terms

BSL Chemistry Glossary - bromine solution - Definition

Bromine Solution is used to identify whether something is an alkane or an alkene. It can help us work out which one it is.

I've been given two conical flasks; they don't have any labels on them so I don't know if they contain alkane or alkene. What I can do to resolve this problem is use this Bromine Solution here.

It's very corrosive and toxic so we have to be careful with it, but it can be used to test them - do you want to see?

In one of these test tubes we have alkane and in the other alkene and, as I said, we don't know which is which ...

Can you see the difference? One of them is still orange whilst the other is yellow; it's decolourised and that's because bromine reacts with the alkene and in doing so it becomes colourless.

The Bromine Solution starts off orange, but then following the reaction it has no colour - it's bonded with the alkene.

This is a really good test and (thankfully) we now know which is alkane and which is alkene.