Equilibrium Question 308
Question: The concentration of $ [{H^{+}}] $ and concentration of $ [O{H^{-}}] $ of a 0.1 aqueous solution of 2% ionised weak acid is [Ionic product of water $ =1\times {10^{-14}}] $ [DPMT 2004; CBSE PMT 1999]
Options:
A) $ 2\times {10^{-3}} $ M and $ 5\times {10^{-12}} $ M
B) $ 1\times 10^{3}\ M\ and\ 3\times {10^{-11}}M $
C) $ 0.02\times {10^{-3}}\ M\ and\ 5\times {10^{-11}}M $
D) $ 3\times {10^{-2}}\ M\ and\ 4\times {10^{-13}}M $
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Answer:
Correct Answer: A
Solution:
Given that Concentration of solution =.1 Degree of ionisation $ =2%=\frac{2}{100}=.02 $ Ionic product of water $ =1\times {10^{-14}} $ Concentration of $ [{H^{+}}] $ = Concentration of solution X degree of ionisation $ =.1\times .02=2\times {10^{-3}}M $ Concentration of $ [O{H^{-}}]=\frac{\text{Ionic product of water}}{[{H^{+}}]} $
$ =\frac{1\times {10^{-14}}}{2\times {10^{-3}}}=0.5\times {10^{-11}}=5\times {10^{-12}}M $ .
