In the reaction of aluminum bromide with ionized sodium bromide which compound is the lewis acid

In the reaction of aluminum bromide with ionized sodium bromide. Aluminum bromide is the Lewis acid

Explanation:

A lewis Acid is a chemical compound that has an empty orbit in its atom composition that allows it to accept electrons from other atoms. this integration is called Lewis adduct. Ionized sodium bromide is not capable of doing that because it has no empty orbital spaces to receive electrons from aluminum bromide. Therefore, aluminum bromide is the correct answer.

test the niobium sample to see wheter it now contains other elements.

This is because when an element emits radiation it transforms into another element or elements (the nucleus changes releasing energy and forming nuclei of new elements).