Prepare a liter of 0.2 M Sodium acetate, and a liter of 0.2 M acetic acid. Densi
ID: 480406 • Letter: P
Question
Prepare a liter of 0.2 M Sodium acetate, and a liter of 0.2 M acetic acid. Density of acetic acid glacial: 1.049. Prepare a series of a 100 ml of acetate buffer from 0.2 M sodium acetate and 0.2 M acidic acid that you prepared in section A in following volumes. Volume of acetic acid X: (10, 30, 50, 70, and 90 ml) Volume of sodium acetate (you need to calculate) (For example X ml of acetic acid, 100-X ml of Na acetate) Measure the pH of each buffer solution using a calibrated pH meter. Calculate the pH of each buffer solution using Henderson-Hasselbalch equation. Fill and calculate the total concentration (Mole) of buffer, acid and the conjugate base of each buffer solution in table below. Present you data in following table.Explanation / Answer
Buffer solution
Solution 1
Acid = 20 ml
acid concentration = 0.2 M x 20 ml/100 ml = 0.04 M
base = 80 ml
base concentration = 0.2 x 80 ml/100 ml = 0.16 M
calculated pH = pKa + log(base/acid)
= 4.75 + log(0.16/0.04) = 5.35
Solution 2
Acid = 40 ml
acid concentration = 0.2 M x 40 ml/100 ml = 0.08 M
base = 60 ml
base concentration = 0.2 x 60 ml/100 ml = 0.12 M
calculated pH = pKa + log(base/acid)
= 4.75 + log(0.12/0.08) = 4.93
Similarly other solutions calculations may be done