What is the ph of a solution made by mixing equal volumes of 1 m sodium acetate and 0.1 m acetic acid? (the pk of acetic acid is 4.

PH of a solution = ?
if equal volumes of 1 m sodium acetate and 0.1 m acetic acid are mixed 
pk of acetic acid is 4.76
for finding pH of a solution,
K = [H+] [A-] / [HA] 
K = [H+] [1] / [1] 
K = H 
pH = pK
now pH is equal to pK
value of pK is given which is 4.76
it means value of pH is also 4.76

Adozen is 1221/12 = 1.751.75 x 12 = 21therefore, 1.75 is the answer.