Calculate the ph of a solution in which [oh−]=7.1×10−3m. express the ph of the solution to two decimal places.

Answer is: pH value of solution is 11.85.
[OH⁻] = 7.1·10⁻³ M;  equilibrium concentration of hydroxide anions.

[OH⁻]·[H⁺] = Kw.

0.0071 mol/L · [H⁺] = 10⁻¹⁴ mol²/L².

[H⁺] = 10⁻¹⁴ mol²/L² ÷ 7.1·10⁻³ mol/L.

[H⁺] = 1.4·10⁻¹² mol/L.

pH = -log[H⁺].

pH = -log(1.4·10⁻¹² mol/L).

pH = 11.85.

If pH is less than seven, solution is acidic; greater than seven, solution is basic; equal seven, solution is neutral.

i think it's letter a.