Why does the equation kw=[H3O+][OH-]=10-14M always hold true?
the value 10-7M comes from the simple fact that this is the concentration of one of the two ions @ 25° C. and i understand that the concentration of one must equal the other for a regular sample of water [H3O+]=[OH-]. and i thought this was because in water, when an H2O ionizes, the same number of H2O's that got donated an H+ is the same number of H2O's that got their H+ stripped away and there are no other additional H+ ion donors, therefore they must be equal. However, for a solution of NaOH, why does the equation still hold? now there IS an additional source of OH ions. so why does kw=[H3O+][OH-]=10-14M still hold?