Question

If rubidium and lithium salts both produce red when held in a flame, how do you distinguish if your sample is a rubidium salt or lithium salt?

Answer 1

Li Chlorides produces a strong red flame but Rb chloride produces a slightly reddish violet flame. if the difference is not obvious enough, i suggest concentrating the Rb solution more and conduct the flame test again. This time the violet hue of the flame should be more apparent.