An unknown solution gives a scarlet-red flame test, but no

Last updated: 7/10/2022

An unknown solution gives a scarlet-red flame test, but no reaction with ammonium carbonate, ammonium phosphate, or ammonium sulfate. The halide test produces no color in the upper hexane layer. Identify (a) the alkali or alkaline earth element, and (b) the halide present in the unknown solution.