posted by Josh G. .
You are asked to prepare a pH=4.00 buffer starting from 1.50 L of 0.0200 \; M solution of benzoic acid C_6 H_5COOH and an excess of sodium benzoate C_ H_5 COONa.
How many grams of sodium benzoate should be added to prepare the buffer? Neglect the small volume change that occurs when the sodium benzoate is added. (in grams)