The pK_(a) value of acetic acid is 4.7447 at 25^(@)C. How would you obtain a buffer of acetic acid and sodium acetate with pH = 4?

The pK_(a) value of acetic acid is 4.7447 at 25^(@)C. How would you ob

1.	The pK_(a) value of acetic acid is 4.7447 at 25^(@)C. How would you obtain a buffer of acetic acid and sodium acetate with pH = 4?
Answer» Solution :`pH=pK_(a)+"log"(["SALT"])/(["Acid"])rArr4=4.7447+"log"(["Salt"])/(["Acid"])` `"log"(["Salt"])/(["Acid"])=4.000-4.7447=-0.7447=1.2553` Taking antilog on both sides, `therefore(["Salt"])/(["Acid"])="anti"log(-1.2553)rArr(["Salt"])/(["Acid"])=0.18` So by MIXING sodium ACETATE and acetic acid in the ratio 0.18 : 1 mole per `dm^(3)`, the BUFFER of pH = 4 is obtainetd.