Question

Color of hydrogen carbonate

Answer 1

Hydrogencarbonate indicator is used to measure carbon dioxide levels in aquatic systems. It is red in equilibrium with atmospheric air. It becomes more orange/yellow with increased carbon dioxide levels. It changes from red through magenta to deep purple as carbon dioxide is removed.

Answer 2

When the carbon dioxide content is higher than 0.04%, the initial red color changes to yellow as the pH becomes more acidic. If the carbon dioxide content is lower than 0.04%, it changes from red to magenta and, in relatively very low carbon dioxide concentrations, to purple.