The percentage of pyridine (C5H5N) that forms pyridinium ion (C5H5N+H) in a 0.10 M aqueous pyridine solution (Kb for C5H5N = 1.7 10-9) is
- 0.0060%
- 0.013%
- 0.77%
- 1.6%
Answer
(2) 0.013%
Solution
C5H5N + H2O C5H5N+H + OH-
For a weak base, = KbC
= 1.7 10-90.10
= 1.7 10-8 = 1.3 10-4
⇒ Percentage ionised = 1.3 10-4 100 = 0.013\%
Answer: (2)