Ammonium ion in flame test yields which color?

• A. Yellow
• B. Violet
• C. Green
• D. No color

Answer: (D)

Flame colors come from electrons in metal ions getting excited and emitting light with characteristic wavelengths. The ammonium ion isn’t a metal ion and, when heated, decomposes to nitrogen and hydrogen rather than producing a distinct visible emission. Because there’s no specific colored emission to observe, the flame appears colorless. Any color you might see would usually come from impurities (like sodium) rather than the ammonium ion itself. So the correct outcome is no color.