What is the colour of the flame of sodium and potassium?

1. A flame test is used to identify the Group 1 metal ions from the chloride-based compounds through the colour of the flame which is volatile in non-luminous flame.
2. The colour of the flame of sodium and potassium is strong persistent orange and lilac (pink). The origin of the flame and flame test procedure is described below:

Flame test procedure:

1. Form a small loop at one end of the Platinum wire.
2. Dip this wire into concentrated Hydrochloric acid and hold it in a non-luminous flame.
3. Repeat the second step until the wire transmits no colour of the flame.
4. Put 2-3 drops of concentrated Hydrochloric acid on the clean transparent glass and make a paste of a little amount of salt on this.
5. Dip clean Platinum wire in the above paste and bring the loop into the non-luminous flame.
6. Form a colour flame that is easily observed through the naked eyes.

Flame formation:

1. Due to strong heating, the electrons promote from a normal unexcited state to a higher orbital level.
2. Energy emission in the form of light when it returns back to the lower level.
3. This light has a particular wavelength which is visible from the naked eyes.