A1br3 and 3k and 3k and 3kbr and a1 are an example of what reaction

It is an example of single displacement reaction.

Explanation:

Single replacement reaction:

A single element replaces another element in a compound.

For example,

The given reaction is as follows.

In the above reaction, aluminium bromide is dissociated into the , these bromide ions are reacted with potassium atoms to form potassium bromide.

Here, only one element  displaces therefore, it is an single displacement reaction.