wiz-icon
MyQuestionIcon
MyQuestionIcon
1
You visited us 1 times! Enjoying our articles? Unlock Full Access!
Question

What is the pH of the solution when 0.2 mol of HCl is added to one litre of a solution containing 1M acetic acid and acetate ions. Assume that the total volume is one litre. Ka(CH3COOH)=1.8×105
log (1.8)=0.255, log (0.66)=0.181

A
9.04
No worries! We‘ve got your back. Try BYJU‘S free classes today!
B
4.56
Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses
C
7.2
No worries! We‘ve got your back. Try BYJU‘S free classes today!
D
6.5
No worries! We‘ve got your back. Try BYJU‘S free classes today!
Open in App
Solution

The correct option is B 4.56
Given, nHCl=0.2 mol,[CH3COOH]=[CH3COO]=1 M
Ka(CH3COOH)=1.8×105
[HCl]=0.21=0.2 M
On adding HCl, the free hydrogen ion will combine with CH3COO ions to form CH3COOH.
Thus, the concentration of acetic acid increases while that of CH3COO decreases.
[CH3COOH]=1+0.2=1.2 mol L1
[Salt]=10.2=0.8 molL1
Applying Henderson's equation:
pH=pKa+log[Salt][Acid]
pH=log Ka+log[Salt][Acid]
pH=log (1.8×105)+log 0.81.2
pH=5log (1.8)+log (0.66)
pH=50.2550.181
pH=4.56

flag
Suggest Corrections
thumbs-up
5
Join BYJU'S Learning Program
Join BYJU'S Learning Program
CrossIcon