the ph of a solution is higher if the concentration of hydroxide ions is... what?
The pH of a solution is higher when the concentration of hydroxide ions [OH−][OH^-][OH−] is greater (i.e., when [OH−][OH^-][OH−] is increased or relatively large).
The pH of a solution is higher when the concentration of hydroxide ions [OH−][OH^-][OH−] is greater (i.e., when [OH−][OH^-][OH−] is increased or relatively large).