Equilibrium Question 743
Question: Equal volumes of three acid solutions of pH 3, 4 and 5 are mixed in a vessel. What will be the $ {H^{+}} $ ion concentration
Options:
A) $ 3.7\times {10^{-3}}M $
B) $ 1.11\times {10^{-3}}M $
C) $ 1.11\times {10^{-4}}M $
D) $ 3.7\times {10^{-4}}M $
Show Answer
Answer:
Correct Answer: D
Solution:
$ [{H^{+}}]={10^{-3}}M,[{H^{+}}]={10^{-4}}M,[{H^{+}}]={10^{-5}}M $ for the given acids. $ M_{mix}V_{mix}=M_1V_1+M_2V_2+M_3V_3 $
$ M_{mix}\times 3={10^{-3}}\times 1+{10^{-4}}\times 1+{10^{-5}}\times 1 $
$ M_{mix}=\frac{{10^{-5}}[100+10+1]}{3}=\frac{111\times {10^{-5}}}{3} $
$ =37\times {10^{-5}}M=3.7\times {10^{-4}}M $
