What color indicates the presence of potassium during a flame test?

During a flame test, potassium ions produce a characteristic lilac color. This response occurs because when potassium is heated in a flame, its electrons gain energy, allowing them to jump to higher energy levels. When these electrons return to their ground state, they release energy in the form of light. The specific wavelengths of light emitted correspond to the lilac color.

This lilac coloration is distinct from those produced by other metal ions. For instance, sodium produces a bright yellow flame, while lithium gives a red flame, and copper typically results in a green or blue flame. The unique spectrum of light emitted by potassium helps chemists identify its presence in a sample effectively during qualitative analysis.