If the concentration of OH- ions in the reaction Fe(OH)3(s) Fe3+(aq) + 3OH-(aq) is decreased by 1/4 times, then equilibrium concentration of Fe3+ will increase by
- 64 times
- 4 times
- 8 times
- 16 times
Answer
(1) 64 times
Solution
K = [Fe3+][OH-]3 (constant at a given temperature)
When [OH-] becomes 14 of its value:
K = [Fe3+]' ( [OH-]4 )3
⇒ [Fe3+]' = 43 [Fe3+] = 64 [Fe3+]
∴ [Fe3+] increases 64 times.
Answer: (1)