Acids and Bases - pH and pOH Calculations

Question 1

note

Answer 1

• pH + pOH = 14
• pH = -log[H+]
• [H+] = 10^-pH
• pOH = -log[OH-]
• [OH-] = 10^-pOH
• [H+][OH-] = 1.0*10^-14

Question 2

what is the pOH and pH of 1/7*10^-4 M NaOH

Answer 2

• pOH = -log[OH-]
• pOH = -log[1.7*10^-4 M]
• pOH = 3.77
• pH = 14 - pOH = 10.23

Question 3

what is the pOH of a 5.2*10^-12 M H+ solution?

Answer 3

• pH = -log[H+]
• pH = -log[5.2*10^-12]
• pH = 11.28
• pOH = 14 - 11.28 = 2.72

Question 4

what is the [OH-], if the pH of a solution is 4.50?

Answer 4

• pOH = 14 - pH
• pOH = 14 - 4.5 = 9.5
• [OH-] = 10^-pOH = 10^-9.5
• [OH-] = 3.2*10^-10 M