What causes the flame colors and the spectra?

When the atoms of a gas or vapor are excited, for instance by heating or by applying an electrical field, their electrons are able to move from their ground state to higher energy levels. ... This energy corresponds to particular wavelengths of light, and so produces particular colors of light.

pH is a measure of the amount of Hydrogen ions (H+) in a solution. ... Even in pure water ions tend to form due to random processes (producing some H+ and OH- ions). The amount of H+ that is made in pure water is about equal to a pH of 7. That's why 7 is neutral.

Explanation:

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