Mahesh Godavarti

Did you ever stick a straw in soapy water and blow into the straw? Did you see how the water foamed and bubbled as you blew air into the straw?

This might lead you to believe that air in water causes bubbles. Is something similar causing bubbles to form when citric acid is added to baking soda?

Let's do a Google search using the phrase "Why does it bubble when you mix citric acid with baking soda?"

We get the first result from Google as follows:

Let's understand what the Google result is telling us.

First, we have to understand that carbon dioxide is a gas (so, it's like air) (you can search for "What is carbon dioxide?" in Google).

Next, let's find out what "Suds" are. Suds are essentially bubbles in soapy water (you can search for "What are suds?" in Google or look them up in a dictionary).

So, we have carbon dioxide that play the role of "air" and suds that play the role of "bubbles". What plays the role of "water" here? That would be the citric acid because it is a liquid. Essentially, any gas trapped in a liquid forms bubbles.

Google tells us that citric acid added to baking soda gives rise to carbon dioxide. This carbon dioxide forms suds (bubbles that stay) in citric acid.