JEE Main Chemistry question
18 mL of mixture of acetic acid and sodium acetate required 6 mL of 0.1 M NaOH for neutralization of the acid and 12 mL of 0.1 M HCl for reaction with salt, separately. If pKa of the acid is 4.75, what is the pH of the mixture?
Answer: (A)
Solution
mol acid∝0.6 mmol, mol salt∝1.2 mmol. pH=4.75+log(1.2/0.6)=4.75+0.301=5.05.