Titrations and pH Curves Lab.pdf - Titrations and pH Curves...

Titrations and pH Curves Lab
Lauryn McKenna
Ashlynn Adams and Leah Burge
PD 2B
19 February 2020

Analysis
M
1
V
1
=M
2
V
2
[HCl] = .090 M
[CH
3
COOH] = .010 M
Initial pH, pH at equivalence point, ending pH:
Strong Acid (HCl): 1.70, 6.16, 12.6
Weak Acid (CH
3
COOH): 3.44, 9.68, 12.0
At the initial point of the graph, the pH of the weak aid is higher than the initial pH of the strong
acid. This is because the strong acid is very acidic, and the weak acid is not as acidic. At this
point of the solution, for the strong acid, HCl ions are present, and for the weak acid, CH
3
COOH
ions are present. At the equivalence point, the mol NaOH added equals the mol of HCl added
(and mol of CH
3
COOH in the weak acid titration). As more titrant is added, the pH will continue
to rise, since OH - ions will continue to saturate the solution, thus making the solution more basic.
In the weak acid titration, CH
3
COOH has a conjugate base pair, CH
3
COO, so those ions are
present as well, where all the ions dissociate in the strong acid titration.