Question

What is the pH of 250.0mL solution that is 0.0955M HCH3CO2 (Ka=1.8x10-5) and 0.125M NaCH3CO2.

a. Now, 20.0 mL of 0.455 M HCl (aq) is added to the original buffer.

i. Write the neutralization reaction (use the actual species in the reaction).

ii. Find the moles of all species.

Answer 1

a) i.  
ii.
Number of moles of acetic acid originally present in buffer moles.
Number of moles of sodium acetate originally present in buffer moles.
Number of moles of HCl added moles
Out of 0.03125 moles of soldium acetate, 0.0091 moles will react with 0.0091 moles of HCl to form 0.0091 moles of acetic acid and 0.0091 moles of NaCl.
Moles of acetic acid moles.
Moles of sodium acetate moles