In: Chemistry
In an acid base titration experiment, 50.0 ml of a 0.0500 m solution of acetic acid ( ka =7.5 x 10^-5) was titrated with a 0.0500 M solution of NaOH at 25 C. The system will acquire this pH after addition of 20.00 mL of the titrant:
Answer is 4.581
Please show all work
No. of moles of acetic acid initially;
No of moles of NaOH added;
Now, draw the ice table for the reaction,
CH3COOH | |
Initially | 2.5*10-3mol |
When NaOH is added | 2.5*10-3-1*10-3 mol |
Finally | 1.5*10-3 mol |
The conentration of acetic acid= 1.5/(50+20)=0.0214 M
Consider the dissociation of acetic acid;
CH3COOH | CH3COO- + | H+ |
0.0214 M | 0 | 0 |
0.0214-X | X | X |
As x <<< 0.0214, we assume that 0.00214=0.00214-x.
Now, calculate the pH of the system using the fllowing equation,