hi there so this video is about testing for carbon dioxide gas and the reagent that we use to test for carbon dioxide is this colorless liquid which is called a lime water now what I need to do is I need to make some carbon dioxide and then I need to bubble that gas through my lime water now notice that I didn't say that I was gonna add the lime water to the gas or it's gonna add the gas to the lime water doesn't really make sense that way the only thing that makes sense is to say that the gas bubbles through the liquid so I'm gonna make my carbon dioxide from calcium carbonate and some hydrochloric acid and check out the results in the test tube here so hopefully you can see some pretty vigorous bubbling happening here and you can also see that that liquid is no longer completely colorless and getting a nice white precipitate being formed there so lime water in the presence of carbon dioxide turns milky