Purpose of Titration
What you are doing in a titration is you are trying to determine the concentration of an unknown acid (or base) using a base (or acid) of known concentration. A simple example would be like this:
suppose you have NaOH of 0.1000 M concentration (this is your standard, ie. solution of known concentration). you have some HCl of not accurately known concentration (say about 0.1), and you need to find an accurate concentration for it (4 sig figs)
Then you take 25mL of acid and deliver into a conical flask using a pipette.
You fill up your burette with NaOH. Add 2/3 drops phenolthalein to your conical flask. Record your initial reading on burette. Add NaOH from the burette into the flask until the solution becomes very very faint pink that disappears after about 10 seconds. Record final reading on burette.
Usually you'd repeat this 3 or 4 times.
Sample Calculation
1) Initial Volume: 10.15 mL (you always take reading to 2 dp)
Final Volume: 32.55 mL
Volume of NaOH used = 32.55 - 10.15 = 22.40 mL
2) You would do this for ALL your replicates, and then average the volume of NaOH used. Suppose you got 22.35, 22. 60, 25.45, 22.40, you would discard 22.60 because it is too different to others (usually the values should be at least within 0.1 mL)
3) Suppose your average value is 22.25 mL. In this simple example, ratio of OH- to H+ is 1 to 1, therefore:
number of moles of NaOH consumed = number of moles of H+ in the conical flask
moles(NaOH) = 0.02240 x 0.1000 = moles(H+)
[H+] = moles(H+)/0.025
