Equilibrium Question 824
Question: The dissociation constant of 0.1 M acetic acid solution is $ 1.8\times {10^{-5}} $ . If 1 L of this solution is mixed with 0.05 mole of $ HCl $ , what will be pH of mixture- $ [ log5=0.7 ] $
Options:
A) 1.3
B) 2.6
C) 1.9
D) 3.4
Show Answer
Answer:
Correct Answer: A
Solution:
The pH of mixture is due to the $ HCl $ only, because $ CH_3COOH $ is negligibly ionised due to common ion effect. Thus, $ [{H^{+}}]=0.05M=5\times {10^{-2}}M $
$ pH=-log( 5\times {10^{-2}} )=-[ log5+log{10^{-2}} ] $
$ pH=1.3 $
