Question

9.35 Determine the pH of water solutions with the following characteristics. Classify

each solution as acidic, basic, or neutral.

a) [H+] = 1.0 x10-4 M

b) [OH-] = 5.0 x10-2 M

c) [H+] = [OH-]

d) [H+] = 8.0 x10-9 M

e) [OH-] = 4.0 x10-10 M

Answer 1

a) pH = -log[H⁺] = -log(1.0 X 10^-4) = 4

solution is acidic

b) pOH = -log[OH^-] = -log(5.0 X 10^-2) = 1.30

pH = 14 - pOH = 14 - 1.30 = 12.70

solution is besic

c) [H⁺] = [OH^-]

[H⁺] = [OH^-] = x

[H⁺] X [OH^-] = 1 X 10^-14

x² = 1 X 10^-14

x = 1 X10 ^-7

[H⁺] = 1 X10 ^-7

pH = -log[H⁺] = -log(1.0 X 10^-7) = 7

solution is neutral

d)

[H⁺] = 8.0 X10 ^-9

pH = -log[H⁺] = -log(8.0 X 10^-9) = 8.09

solution is Besic

e)

pOH = -log[OH^-] = -log(4.0 X 10^-10) = 9.4

pH = 14 - pOH = 14 - 9.4 = 4.6

solution is Acedic

pH = 1 to 7 solution acedic

pH = 7 solution neutral

pH = 7 to 14 solution besic