Would flame tests be useful for detecting metal ions present in a mixture of metal ions?
In a flame test, different metal give of different wavelengths of light, some of which we can see, visible light from most metals i.e. Cu, Lit and K. Other metals give off light which we can't see, i.e. Mg. However, if two or more metals present gave more than one colour of visible light, it would be hard to distinguish between them to find individual metals and may take several colours as one colour, and therefore take several metals as one different metal.