Equilibrium Question 906
Question: A mixture of weak acid is $ 0.1M $ in $ HCOOH $
$ (K_{a}=1.8\times {10^{-4}}) $ and $ 0.1M $ in $ HOCN(K_{a}=3.1\times {10^{-4}}) $ Hence, $ [H_3{O^{\oplus }}] $ is
Options:
A) $ 7.0\times {10^{-3}}M $
B) $ 4.1\times {10^{-4}}M $
C) $ 0.20M $
D) $ 4.1\times {10^{-3}}M $
Show Answer
Answer:
Correct Answer: A
Solution:
$ [H_3{O^{+}}]=\sqrt{K_1C_1+K_2C_2} $
$ =\sqrt{1.8\times {10^{-4}}\times 0.1+3.1\times {10^{-4}}\times 0.1} $
$ =7\times {10^{-3}}M $
