You are asked to prepare 100 ml of a buffer solution at ph 4.2. on the shelves, you have a set of sodium salts listed in the table below. the pkb of each salt is listed. you also have plenty of a stock solution of 0.50 m hydrochloric acid. a) choose the appropriate sodium salt for your buffer then calculate how much salt (in grams) to add to 100 ml of 0.50 m hcl to create the requested buffer. you may assume no change in volume upon adding your salt. b) how much additional 0.5 m hcl could be added before the buffer is destroyed? (defined as 1 ph unit below the designated buffer ph). sodium salt pko sodium acetate 9.25 sodium benzoate 9.81 sodium formate 10.25 sodium lactate 9.14