Experiments Explained: Volcanic Eruptions

The classic volcano experiment with chemical lenses

A real-life volcano that is very far off the classic volcano experiment that we usually do. (Marc Szeglat / Unsplash)

I think we had seen or done some version of the volcano eruption experiment, whether it is at home or at school. Or if not, maybe you watched a version of it already on YouTube. This is usually done by molding a volcano made of clay with the plastic bottle inside. The plastic bottle is filled with vinegar and red food coloring (for the aesthetic of lava), with the dishwashing soap added. And then BOOM, there you have it, an explosion!

I think we had always learned about this experiment with a geological lens as, surprise surprise, the reaction is in a volcano. But what if I tell you that there is a chemical side to it as well?

But first, to jog our memory a little, you can watch the experiment here:

Volcano Challenge! Classic Baking Soda and Vinegar Volcano / Arizona Science Center

What the volcano reaction boils down into is a reaction between baking soda and the vinegar. Since vinegar is an acid and baking soda is a base¹, they react together through an acid-base reaction. The positively charged hydrogen ions in the vinegar react with the negatively charged bicarbonate ions in order to form carbonic acid and sodium acetate.

The chemical equation between vinegar (acetic acid) and baking soda (sodium bicarbonate) resulting in carbonic acid and sodium acetate.

However, that’s not it! The carbonic acid separates² into two compounds: water and carbon dioxide. The carbon dioxide gives the bubbles and the foam that is always a part of an iconic volcano experiment. This is because the carbon dioxide rises to the top in order to escape, just like the carbon dioxide in carbonated drinks (think of Coca-Cola or other soft-drinks!).

The chemical equation for the decomposition of carbonic acid, resulting in water and carbon dioxide.

Therefore, we can see that the whole chemical equation for the popular volcanic eruption experiment is:

The whole chemical equation for the volcanic eruption experiment.

So, next time this explosive experiment, whether by yourself or by endlessly scrolling through YouTube, you now know the science behind it.

The chemical equations are made through LaTex to Image converter at latex2image.joeraut.com.

Sources:

[1] Student RLCMUBG. Why do baking soda and vinegar ‘explode’? [Internet]. Columbia Daily Tribune. Columbia Daily Tribune; 2017 [cited 2021 May 23]. Available from: www.columbiatribune.com/news/20171010/why-do-baking-soda-and-vinegar-explode

[2] What Happens When You Mix Vinegar and Baking Soda? [Internet]. Wonderopolis. Wonderopolis; [cited 2021 May 23]. Available from: wonderopolis.org/wonder/what-happens-when-you-mix-vinegar-and-baking-soda