1. Calculate the pH of a buffer solution made by adding 5.0g of anhydrous sodium acetate (NaC2H3O2) to 50mL of 0.100 M acedtic acid. Assume there is no change in volume on adding the salt to the acid. pKa for acetic acid is 4.7.

Buffer capacity refers to the amount of acid or base a buffer can absorb without a significant pH change. A 0.5M buffer can absorb 5x as much acid or base as a 0.1M buffer for a given pH chnage.

You are given 60mL of 0.50M phosphate buffer, pH= 6.83. The starting composition of the buffer, both in terms of concentration and molar quantity of two major phosphate species is:
Concentration of HPO4^2-= 0.304M
Concentration of H2PO4-= 0.196M
Molar quantity of HPO4^2-= 18.2 mmol
Molar quantity of H2PO4-= 11.8 mmol

a) You add 1.7 mL of 1.00 M HCL to the buffer. Calculate the molar quantity of H30+ added as HCL and the final molar quantity of HPO4^2- and H2PO4- at equilibrium?

b) What is the new HPO4^2-/H2PO4- ratio and new pH of solution? The pKa of H2PO4- is 6.64. Use henderson-hasselbach.

C) Now take a fresh 60mL of the 0.50M pH of 6.83 buffer and add 3.7mL of 1.00M NaOH. Caclulate the new pH of the solution.