[Anson]

When carbon dioxide dissolves in water, forms carbonic acid. If large amount of carbon dioxide keep dissolves in water (saturated condition), what is the lowest pH level it can get? higher than 7 or lower, considering carbonic also act as buffer in water.

THANK YOU

[jubba]

You should try look up the threshold of solubility for carbon dioxide in a data sheet. Then find the percentage of dissasociation. From their you can work out the maximum ph possible

[Borek]

Then find the percentage of dissasociation. From their you can work out the maximum ph possible

Not so easy, although you are more - or less - corect.

http://www.chembuddy.com/?left=pH-calculation&right=pH-polyprotic-acid-base

http://www.chembuddy.com/?left=pH-calculation&right=pH-polyprotic-simplified