Respuesta :

transitionstate
As we know, NaOH is a strong Base and completely dissociates in water as given below,

                            NaOH + H₂O    →   Na⁺ ₍aq₎  +  OH⁻ ₍aq₎

So, the concentration of OH⁻ Ions will be the same as that the concentration of NaOH i.e. 0.018 M.
So,
                                     [OH⁻]  =  0.018 M