# Acids And Bases

1. Sep 20, 2004

### Jack16

Could You Help Me Out Please...

The Value of Kw ,the ionic product of water,increases with temperature.Will the pH of pure water be greater or less than 7 at 100*C?

2. Sep 20, 2004

### chem_tr

Hello,

It will be slightly more acidic, although H+ and OH- will be equally dissociated from water; because pH is calculated according to [H+]. Let me assume that in a higher temperature, the ionic product changes to 1,8.10-14. When you calculate the -log value of this, you'll find ca. 6,87. This shows that the pH value will be lower in higher temperatures.

In addition, in a higher temperature, the absorption of CO2 will be much higher, then the formation of carbonic acid, H2CO3, will cause the resulting aqueous solution to be even more acidic than that in the ambient temperature.

Regards, chem_tr

Last edited: Sep 20, 2004