Buffers Day 4
1. A buffer contains 0.10 mol of acetic acid and 0.13 mol of sodium acetate in 1.00L. What is the
pH of this buffer?
a. What is the pH of the buffer after the addition of 0.02 mol of KOH?
b. What is the pH of the buffer after the addition of 0.02 mol HNO3
2. A buffer contains 0.15 mol of propionic acid (HC3H5O2) Ka = 1.3 x 10-5 and 0.10 mol of sodium
propionate (NaC3H5O2) in 1.2 L.
a. What is the pH of this buffer?
b. What is the pH of the buffer after the addition of 0.01 mol of NaOH?
c. What is the pH of the buffer after the addition of 0.01 mol of HI?
3. What is the pH of 0.15M acetic acid to which 1.56 g of sodium acetate, NaC2H3O2, has been
added?
4. Calculate the pH of a solution that has an acetic acid concentration of 0050M and a sodium
acetate concentration of 0.075M.
5. Calculate the pH of a solution that has an ammonium chloride concentration of 0.050M and an
ammonia concentration of 0.045M.
6. What is the pH of a solution that has a formic acid concentration of 0.050M and a sodium formate
concentration of 0.035M?
7. Which of the following combinations would be the best to buffer the pH at approximately
a. 9
b. 4
i. HCl and NaCl
ii. NH3 and NH4Cl
iii. HC2H3O2 and NaC2H3O2
8. A buffer is made by adding 4.95 g of sodium acetate (NaC2H3O2) to 250mL of 0.150M acetic
acid.
a. What is the pH of the buffer solution?
b. What is the pH of the solution if you add 0.082grams of NaOH to the solution?
9. A buffer is prepared by adding 0.125 mol of ammonium chloride to 500 mL of 0.5M ammonia.
a. What is the pH of the buffer?
b. If 0.0100 mol of HCl gas is bubbled into the 00mL of the buffer, what is the new pH of
the solution?
10. If a buffer solution contains 0.15M HC2H3O2 and 0.25M NaC2H3O2, what is the pH of the
solution?
11. A buffer is prepared containing 0.25M NH3 and 0.30M (NH4)2O. What is the pH of the solution?
12. A buffer solution is prepared by adding 0.40M HC2H3O2 to 0.30M NaC2H3O2.
a. What is the pH of the buffer solution?
b. 0.20M HCl is added to the solution, what is the new pH?
13. A buffer is prepared by adding 115 mL of 0.30M NH3to 135ml of 0.15M NH4NO3. What is the
pH?
14. What is the pH of a solution that contains 0.10M NH3 and 0.10M NH4Cl?
a. What is the pH after you add 0.02 mol of HCl?