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Chemistry Forums for Students => Undergraduate General Chemistry Forum => Topic started by: Corribus on October 23, 2022, 11:30:26 AM

Title: carbon dioxide detection
Post by: Corribus on October 23, 2022, 11:30:26 AM

I have a 15 mL mixture containing sucrose and a few other substances in a sealed scintillation vial. After some time the cap became distended. I believe it is because sucrose is being oxidized, resulting in generation of carbon dioxide. Anyone have any suggestions about how I can confirm that the gas in the headspace is carbon dioxide? I have a bit of a hurry so I'm looking for something simple, inexpensive, and I don't want to order any sensors or anything.

Title: Re: carbon dioxide detection
Post by: Hunter2 on October 23, 2022, 02:05:55 PM

Add a hose and guide the gas through a solution of bariumhydroxide. Maybe can use a fermentation tube what is used to make vine.
 If CO2 is present a precipitate  of bariumcarbonate takes place

Title: Re: carbon dioxide detection
Post by: Corribus on October 23, 2022, 02:22:59 PM

Clever, I like it. But I am not sure I have barium hydroxide in the lab. I will have to check tomorrow.

I wonder if I can do the same thing with calcium carbonate, starting with calcium chloride?

Title: Re: carbon dioxide detection
Post by: Hunter2 on October 23, 2022, 02:27:26 PM

Calciumhydroxide would also work. But preparation is more difficult  to get a clear solution because of soloubility

Title: Re: carbon dioxide detection
Post by: Corribus on October 23, 2022, 02:28:55 PM

Yeah I edited my post above. I was thinking calcium chloride, which is pretty soluble.

Title: Re: carbon dioxide detection
Post by: Hunter2 on October 23, 2022, 02:35:40 PM

No, it has to be alcaline. Because carbonic acid is a weak acid in comparrison of hydrochloric acid.

CaCl2  + H2O + CO2 <= CaCO3 + 2 HCl , will work Opposit.

But Ca(OH)2 + CO2 => CaCO3 + H2O will work