In which of the following images does the
result of a flame test indicate the presence of barium?
In a flame test, we’re adding an ionic
solid, a powder perhaps, to a flame. And we’re looking at the colour
change. Each colour is characteristic of certain
ions. A is a red flame. B is an orange or yellow. C is green. D is blue. And E is purple. To answer this question, we’re going to
need to recall what flame colour is characteristic of the barium two plus ion.
A green flame is indicative of barium two
plus, boron three plus, or copper two plus. So, we can be pretty sure that the green
flame is the one most likely to indicate the presence of barium. A red flame is associated with lithium
plus or strontium two plus. An orange or yellow flame is indicative
of sodium plus or calcium two plus. A Blue flame like this is most likely
indicative of copper plus. While a purple flame, depending on the
depth of its colour, is more likely to indicate potassium plus, rubidium plus or cesium
So, of the images given, the one that
indicates the presence of barium is flame C, the one with the green flame.