What is the pH of a KOH solution that has [H+] = 1.87 × 10–13 M? Round to the nearest tenth.

What is the pOH of a KOH solution that has [OH–] = 5.81 ×10–3M? Round to the nearest hundredth.

What is the pH of a solution of NaCl that has [H+] = 1.00 × 10–7 M? Round to the nearest hundredth.