After your freakish friend (from the other pH problem) found out that it was carbon dioxide in the air that made his water acidic, he made sure that all his jars are air-tight and vacuumed out all the air in his jars immediately after the purification. How big of a freak is that?!

During one hot summer day, you and he just finished playing basketball. You went over to his house and again, he offers you a glass of his purified water. And to ensure that it's pure, he measures the pH of it right after he pours it out (so that it doesn't get in contact with the air too long).

And again, the pH of the water is not 7! What happened this time?

I'm not sure if the chemistry is correct on this, but maybe when he vacuumed all the air out of the comtainer it caused the water to ionize. Since the vapour pressure of hydrogen is different from oxygen, more of one or the other element would evaporate out of solution and become a gas, filling the empty space in the container, thereby causing the remaining water to be slightly acidic or basic.

Posted by Kyle on 2003-02-15 16:46:04