In a flame test for potassium, which color is observed?

In a flame test for potassium, which color is observed?

• A. Lilac
• B. Yellow
• C. Crimson-red
• D. Orange-red

Answer: (A)

Flame tests rely on metal ions absorbing energy in the flame and then emitting light as electrons drop back to lower energy levels. For potassium, the emitted light falls mainly in the violet part of the spectrum, so the flame appears as a pale purple—often described as lilac. This lilac color is a distinctive signal of potassium when the sample is clean and sodium contamination isn’t masking it. If sodium were present, its strong yellow emission could overwhelm the potassium color. Other metals produce different flame colors (for example, lithium gives crimson-red, calcium orange-red, copper blue-green), so the lilac hue helps identify potassium specifically.

Flame tests rely on metal ions absorbing energy in the flame and then emitting light as electrons drop back to lower energy levels. For potassium, the emitted light falls mainly in the violet part of the spectrum, so the flame appears as a pale purple—often described as lilac. This lilac color is a distinctive signal of potassium when the sample is clean and sodium contamination isn’t masking it. If sodium were present, its strong yellow emission could overwhelm the potassium color. Other metals produce different flame colors (for example, lithium gives crimson-red, calcium orange-red, copper blue-green), so the lilac hue helps identify potassium specifically.