In: Chemistry
Calculate the pH of a solution made by combining 45 mL of 0.3 F acetic acid with 28 mL of 0.4 F sodium acetate. Assume that pKa for acetic acid is 5.00. ?
CH3COOH
M1 = 0.3F M2 =
V1 = 45ml V2 = 45+28 = 73ml
M1V1 = M2V2
M2 = M1V1/V2
= 0.3*45/73
CH3COONa
M1 = 0.4F M2 =
V1 = 28ml V2 = 28 +45 = 73ml
M1V1 = M2V2
M2 = M1V1/V2
= 0.4*28/73
PH = Pka + log[CH3COONa]/[CH3COOH]
= 5 + log(0.4*28/73)/(0.3*45/73)
= 5 + log0.4*28/0.3*45
= 5+ log11.2/13.5
= 5 -0.08111 = 4.918 >>>>answer