When carbon dioxide dissolves in water, it combines with H₂O to produce carbonic acid (H₂CO₃). Carbonic acid dissociates to form aquated hydrogen carbonate ions, (HCO₃^-), which can ionize further to form aquated carbonate ions (CO₃^2-), an integral component in the shells of marine creatures. This is summarized by the following set of equations:

The oceans have absorbed 33-50% of all the CO₂ humans have produced by burning fossil fuels since the Industrial Revolution. As such, the effects of increased anthropogenic CO₂ emissions have not been fully felt.

The above video shows what happens when CO₂ is bubbled through water coloured with a universal pH indicator. Before watching the video, use the example pH indicator strip underneath the video to predict what will happen to the water in the beaker as CO₂ is bubbled through it.

Click here to perform a virtual version of this experiment yourself! Manipulate the [H₃O⁺_(aq)] slider and watch what happens to the pH as you are bubbling CO₂ through the water.

Question: Why does the colour of the indicator in the water change? Describe what is happening in the water during the color change using the visualizations and equilibrium equation shown above as a guide.