Equilibrium Question 774
Question: 20 mL of 0.2 M $ NaOH $ are added to 50 mL of 0.2 M $ CH_2COOH $
$ (K_{a}=1.8\times 10^{-5}) $ the pH of the solution is
Options:
A) 4.56
B) 4.73
C) 9.45
D) 6.78
Show Answer
Answer:
Correct Answer: A
Solution:
$ Conc.=\frac{Millimoles}{Total,Volume} $
$ [CH_3COOH]=\frac{6}{70};[CH_3COONa]=\frac{4}{70} $
$ pH=-\log(1.8\times {10^{-5}})+\log\frac{4/70}{6/70},pH=4.56 $
BETA
