Kw - applies to solutions other than 100% water?

[Dayna Pham 1I]

For 12.21 in the Sixth Edition, we are suppose to solve for either [H3O+] or [OH-] using the Kw relationship, [H3O+][OH-] = 10^-14. Can we use this relationship to solutions other than 100% water? I thought that Kw was only for water but it doesn't say in the question whether the solution is water-based or not.

[Anushi Patel 1J]

I think we are supposed to assume the solvent is water. Also, I think you can always use Kw to relate [H3O+] and [OH-].

[Kyle Golden Dis 2G]

The question implies that it is about water since it has hydroxide and hydronium ion.

[Angela Grant 1D]

Kw implies that the solution is water since the expression represents the autoprotolysis of water