cal culate the ph of a mixture of 100 ml distilled water and 2 ml of 2M of NaOH

(NaOH) = 2M x (2 mL/100 mL) = ?

(OH^-) = (NaOH)
pOH = -log(OH^-)
pH + pOH = pKw = 14.
You know pOH and pKw, solve for pH.