Question

A buffer solution is prepared by mixing 2.50 mL of 2.00M sodium acetate with 3.30mL of 0.500M HCl and diluting the buffer with water to a final volume of 500.0mL. pK acetic acid: 4.76

what is ph of buffer?
what is final concentration of buffer?

Answer 1

acetate = Ac
acetic acid = HAc
-------------------------
millimols Ac = mL x M = 5.00
mmols HCl = 3.30 x 0.5 = about 1.6

..........Ac + H^+ ==> HAc
I........5.00..1.6.....0
C........-1.6.-1.6.....+1.6
E........3.4....0.....1.6

pH = pKa + log(3.4/1.6)

final (Ac) = millimols/mL = 3.40/5.80=?
final (HCl) = 1.60/5.80 = ?
final concn buffer = M Ac + M HCl