Question

1). Calculate the initial and final pH when 5.0, 10.0, and 100mL of 0.100M HCL is added to
(a) 100mL of water
(b) 100mL of a buffer which is 1.50M acetic acid and 1.20M sodium acetate

2). Develop a recipe for making this buffer from acetic acid, sodium hydroxide, and water

Answer 1

1a. 5 mL added.
(HCl) = 0.1M x 5 mL/105 mL = ?. Convert to pH.
10 mL and 100 mL are done the same way.

1b. millimols HCl added = 5 x 0.1 =0.5
mmols HAc = mL x M = about 150
mmols Ac&- = about 120

.......Ac^- + H^+ ==> HAc
I......120....0........150
add..........0.5..........
C.....-0.5..-0.5.......+0.5
E......119.5..0........150.5

Substitute the E line into the Henderson-Hasselbalch equation and solve for pH.
The 10 and 100 mL are done the same way.

Answer 2

Dr.Bob222, thank you for the assistance with 1a and 1b, however, I'm kind of confused with 2! What does recipe entail? A description? A series of calculations?