Question 21M.2.hl.TZ1.a

K_a = 10^−4.87 / 1.35 × 10⁻⁵ ✔

[H⁺] = «$\sqrt{1.35\times {10}^{-5}\times 0.001}=\sqrt{1.35\times {10}^{-8}}=$» 1.16 × 10⁻⁴ «mol dm⁻³» ✔

pH = 3.94 ✔

Accept alternative methods of calculation.

Award [3] for correct final answer.

Award [3] for 3.96 {answer if solved by quadratic}.