Question

Calculate [H+], [OH-] & ph of strong acids strong base.

Answer 1

The question is too general.

Strong acids and strong bases ionize 100%; therefore, the H^+ of HCl, HNO3, HClO4, etc is just (HCl), (HClO4), (HNO3), etc.
Same for bases. The (OH^-) of KOH is just (KOH).