pH of a buffer solution decreases by 0.02 units when 0.12 g of acetic acid is added to 250 mL of a buffer solution of acetic acid and potassium acetate at `27^(circ)C`. The buffer capacity of the solution is

Options

A. 0.1
B. 10
C. 1
D. 0.4

Answer

D

Explanation

Change in pH(`DeltapH`) = 0.02
No. of moles of acid added per litre,
`Delta C = wt/Mwt xx 1000/V = 0.12/60 xx 1000/250 = 1/125`
Buffer capacity`(beta) = DeltaC/DeltapH`
`:. beta = (1/125)/0.02 = 0.4`