You are cooking spaghetti in water you have salted with nacl. you notice that when the water boils over, it causes the flame of the gas burner to turn bright orange. how would you explain the appearance of a color in the flame.

NaCl solution contains sodium ions. A sodium ion is formed when a sodium atom loses one electron.

When the solution is spilled over the hot flame, some of the Na ions regain their lost electron and form Na atoms. The electrons in these neutral Na atoms are excited due to the high energy of the flame. They absorb this energy and jump to a higher level.

As they come back to their original level, they emit energy in the form of light.

This emitted energy or the light is unique for a particular metal. In case of sodium, the light is bright yellow-orange in color.

The same principle is used in flame test.

And therefore, when the water boils over, it causes the flame to turn bright orange.