Flame Test?

Question

I need to know what the compound sodium nitrate would look like, through a cobalt glass, when placed in a flame.
Ex.- copper nitrate= green

Answer 1

Sodium nitrate in a flame test through cobalt glass would be invisible. The intense yellow light of of sodium would not come through. The purpose of the cobalt glass is to let the lilac light of potassium shine through when the two elements are there together. If potassium is not there, you see nothing. If potassium is there, then you see the lilac flame, no matter how much sodium there is trying to swamp it out.