Equilibrium Question 306
Question: The dissociation of water at $ 25^{o}C $ is $ 1.9\times {10^{-7}}% $ and the density of water is $ 1.0,g/cm^{3}. $ The ionisation constant of water is [IIT 1995]
Options:
A) $ 3.42\times {10^{-6}} $
B) $ 3.42\times {10^{-8}} $
C) $ 1.00\times {10^{-14}} $
D) $ 2.00\times {10^{-16}} $
Show Answer
Answer:
Correct Answer: D
Solution:
$ \alpha =1.9\times {10^{-9}} $ ; $ C=\frac{1000}{18} $
$ K=\frac{[{H^{+}}][O{H^{-}}]}{(H_2O)}=C{{\alpha }^{2}} $
$ =1.9\times {10^{-9}}\times 1.9\times {10^{-9}}\times \frac{1000}{18} $
$ =2.0\times {10^{-16}} $ .
