Sodium chloride imparts a yellow color to the Bunsen flame. This can be interpreted due to the :emission of excess energy absorbed as a radiation in the visible regionlow ionisation of energy of sodiumphoto sensitivity of sodiumsublimation of metalic sodi (2024)
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Sodium chloride imparts a yellow color to the Bunsen flame. This can be interpreted due to the emission of excess energy absorbed as a radiation in the visible region.
When an alkali or akaline earth metal (or its salt) is introduced in the flame, the valence electrons of the metal absorbs energy and are excited to the higher energy level. When excited electrons return to their ground state, they release the absorbed energy as visible light.
Because sodium chloride crystals suffer from a metal excess defect when heated with sodium vapours, sodium chloride takes on a yellow colour when heated. It looks yellow due to an electrical transition in the excited state of the sodium atom. The Bunsen flame takes on a yellow hue when sodium chloride is added.
Sodium metal burns with air giving golden yellow flame. Why? Because excited sodium atoms emit light at two wavelengths that are close to 589 nm. This is also the reason for the strong yellow light emitted in low-pressure sodium lamps (not produced any more).
If the color is turned to close or partially close the air hole, there's limited oxygen provided to the combustion reaction, resulting in incomplete combustion. This will produce a yellow flame from the Bunsen burner.
If you have a very hot Bunsen burner the sodium chloride may begin to melt if you heat it strongly enough. Its melting point is about at the limit of Bunsen burner temperatures.
The orange color is produced by sodium atoms in the flame. It's caused by excited electrons in the sodium atoms falling back to lower energy levels and releasing orange visible light. No visible light is emitted or seen when excited electrons in chloride ions fall back to their ground state.
The colour of the light depends upon the metal (lithium(I) gives a magenta red-pink flame, calcium an orange red flame, potassium a lilac flame, strontium a crimson red flame, copper(II) gives a blue or green flame and sodium(I) gives a yellow flame).
Most fuels contain sodium (e.g., candles and wood), so you're familiar with the yellow color this metal adds to a flame. The color is muted when sodium salts are placed in a blue flame, such as a Bunsen burner or alcohol lamp. Be aware, sodium yellow overwhelms other colors.
An orange, yellow or red flame means incomplete combustion of the gas. Again, remembering back to high school, if you starved the Bunsen burner of air, the combustion process was incomplete and the gas flame colour burned as sooty yellow or red flames and at a cooler temperature.
Sodium chloride emits an intense yellow color when it is heated with a strong Bunsen burner flame. Streetlamps produce a similar bright-yellow color when they are switched on because they also contain sodium atoms.
The colour of the salt depends on the ions in the salts. Here we consider dry sodium chloride and the solutions of sodium nitrate and sodium chloride all impart the same color to the flame, because both cases have the same sodium ion.
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