To prepare a buffer solution of pH=4.04, amount of Barium acetate to be added to 100 mL of 0.1 M acetic acid solution `[pK_b(CH_(3)COO^(-))=9.26]` is:

Options

A. 0.05 mole
B. 0.025 mole
C. 0.1 mole
D. 0.005 mole

Answer

B

Explanation

For the buffer solution of `CH_3COOH & CH_3COO^(-)`
`pH=pK_a + "log" ([CH_3COOH])/([CH_3COO^(-)])" " implies 4.04=4.74+"log" ((100xx0.1))/(m."moles of " CH_3COO^(-))`
`implies` m.moles of `CH_3COO^(-)=50 " " therefore` moles of `(CH_3COO)_2` Ba required =0.025.