What is the pH when 25.0 mL of 0.2 M of CH3COOH has been titrated with 35.0 mL of 0.1 M NaOH ? pKa(CH3COOH)=4.752 log2.333=0.368
A
7
No worries! We‘ve got your back. Try BYJU‘S free classes today!
B
3.45
No worries! We‘ve got your back. Try BYJU‘S free classes today!
C
5.12
Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses
D
6.52
No worries! We‘ve got your back. Try BYJU‘S free classes today!
Open in App
Solution
The correct option is C 5.12 1) Determine moles of acetic acid and NaOH before mixing: CH3COOH:(0.2molL−1)×(0.025L)=0.005mol NaOH:(0.1molL−1)×(0.035L)=0.0035mol
2) Determine moles of acetic acid and sodium acetate after mixing: CH3COOH:0.005mol−0.0035mol=0.0015mol CH3COONa:0.0035mol
3) Use the Henderson - Hasselbalch Equation: pH=pKa+log[[conjugate base][acid]] pH=pKa+log[[CH3COONa][CH3COOH]] pH=4.752+log0.00350.0600.00150.060 pH=4.752+log2.333 pH=4.752+0.368=5.120