Will pure water have a pH greater or less than 7 at 100°C?

[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?

 

[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