At 25 , the dissociation constant of a base, BOH, is 1.0 10-12. The concentration of hydroxyl ions in 0.01 M aqueous solution of the base would be
- 1.0 10-5 mol L-1
- 1.0 10-6 mol L-1
- 2.0 10-6 mol L-1
- 1.0 10-7 mol L-1
Answer
(4) 1.0 10-7 mol L-1
Solution
As per NCERT, for a weak base BOH B+ + OH- with small degree of ionisation:
[OH-] = C = Kb C
[OH-] = 1.0 10-12 0.01
[OH-] = 1.0 10-14
∴ [OH-] = 1.0 10-7 mol L-1
Answer: (4)