pH Scale

Ion product constant for water K w H 2 O  H + + OH - K w = [H + ] [OH - ] = 1.0 X mol/L Since [H + ] = [OH - ] for water Then each equals 1.0 X M Water is neutral (neither acid or base)

The [H + ] or [OH - ] can be calculated if one is known…. Example: if [H + ] = 1.0 X Then, [OH - ] = 1.0 X because [H + ] [OH - ] must = 1.0 X

If the [H + ] is larger than the [OH - ] then the solution is acid If the [OH - ] is larger than the [H + ], then the solution is basic

pH Concept that describes how acidic or how basic a solution is… pH = -log [H + ] Defined in terms of H + pH 7 base

pH scale [H + ] = [OH - ] = [H + ] > 1.0 X [OH - ] > 1.0 X acidicbasic

pOH pOH = -log [OH - ] pH + pOH = – pOH = pH