Asolution with a hydroxide ion concentration of 4.15 × 10-3 m is and has a hydrogen ion concentration of

When,
             [OH⁻]  =  1.4 × 10⁻³
Then,
             pOH  =  -log (1.4 × 10⁻³)

             pOH  =  2.85
Also,
             pH + pOH  =  14
So,
             pH  =  14 - 2.85

             pH  =  11.15

As pH is greater than 7, so the solution is Basic in Nature.

Calculating for concentration of [H⁺],
As,
            pH  =  -log [H⁺]
Or,
            11.15  =  -log [H⁺]

Taking Antilog on both sides,

            [H⁺]  =  7.07 × 10⁻¹² M

Result:
           A solution with a hydroxide ion concentration of 4.15 × 10⁻³ M is Basic and has a hydrogen ion concentration of 7.07 × 10⁻¹² M.

Happy new years every one