Equilibrium Question 461
Question: The $ pH $ of a solution obtained by mixing $ 50ml $ of $ 0.4NHCl $ and $ 50ml $ of $ 0.2NNaOH $ is [KCET 1996]
Options:
A) $ -\log 2 $
B) $ -\log 0.2 $
C) 1.0
D) 2.0
Show Answer
Answer:
Correct Answer: C
Solution:
N.eq. for $ HCl=\frac{0.4}{1000}\times 50=0.02 $ N.eq. for $ NaOH=\frac{0.2}{1000}\times 50=0.1 $ Now $ [O{H^{-}}] $ left $ =0.1-0.02 $
$ [O{H^{-}}]=.08=8\times {10^{-2}} $ M $ pOH=-\log 8\times {10^{-2}} $ M ; $ pOH=1.0 $
