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 pK_a of the acid is 4.75, what is the pH of the mixture?

(a) 5.05

(b) 4.75

(c) 4.5 

(d) 4.6

Answer 1

Correct option: (a) 5.05

Explanation: 

m Mole of acid = 6 x 0.1 = 0.6

m Mole of salt = 12 x 0.1 = 1.2