Chapter 14, Problem 25QAP

A sodium hydrogen carbonate-sodium carbonate buffer is to be prepared with a pH of 9.40.

(a) What must the $\left[{\text{HCO}}_3{}^{-}\right]/\left[{\text{CO}}_3{}^{2-}\right]$ratio be?

(b) How many moles of sodium hydrogen carbonate must be added to a liter of 0.225 M Na₂CO₃ to give this pH?

(c) How many grams of sodium carbonate must be added to 475 mL of 0.336 M NaHCO₃ to give this pH? (Assume no volume change.)

(d) What volume of 0.200 M NaHCO₃ must be added to 735 mL of a 0.139 M solution of Na₂CO₃ to give this pH? (Assume that volumes are additive.)