Question

What is the observation that will made when bromine added to potassium fluoride?

Answer 1

Aside from turning the solution of `KF` brown-ish due to adding the Bromine, not much more will happen.

Explanation:

This is an example of a displacement reaction where the more reactive element will replace a less reactive one. In this case, we have two halogens, Bromine and Fluorine.

As we already have an ionic compound, `KF`, between Potassium and Fluorine, the Bromine will attempt to replace the Fluorine to form Potassium bromide, `KBr`- but it will fail to displace the fluorine as bromine is not as reactive as fluorine, being found lower down in group 17.

As group 17 elements become less reactive as you go down the group, we can conclude that bromine is the less reactive species. So adding bromine will not cause a displacement reaction.

So, aside from turning the solution (assuming the `KF` is in solution) brown-orange due to the addition of Bromine in solution, nothing else will happen.