Titrations

So, what is a titration? Well, a titration is a way of finding the concentration of an unknown substance using a substance whose concentration you do know. For example, imagine we have a given volume of HCl(hydrochloric acid) but we don't know its concentration. Then, imagine we have a known concentration of NaOH(sodium hydroxide) with us. We can add incremental amounts of NaOH to the container which holds HCl to find the volume of NaOH(the difference between its original and final volumes). We can also add an indicator, which is an inert substance which changes the color of the solution near the equivalence point. If the solution's color changes, that indicates we've reached a point known as the titration equivalence point, where the moles(concentration x volume) of each substance in solution is equal. Since we know the concentration and volume of NaOH and the volume of HCl, we can find the concentration of HCl.

In this titration, our analyte would be HCl. An analyte is the substance you're trying to find the concentration of or just analyze in general during a titration. The titrant is NaOH. The titrant is the substance you add to study the analyte.

A titration curve is just a plot of the solution pH vs the volume of titrant added, usually in mL(milliliters).

Acid-base titration curves have very similar properties to buffers. Usually, the titration sees a gradual change in pH until the equivalence point, where the solution's pH drastically changes, as seen below with the titration of a weak acid with strong base NaOH.

The titration usually involve any combination of weak and strong acids and bases. However, a very non-conforming titration type is one where a weak acid/base titrant is used to study a weak base/acid analyte. This is not optimal because the curve at the equivalent point isn't very step so it's hard to determine the equivalence point. Additionally, indicators have pH ranges so because the curve isn't steep there, the pH won't change drastically so there could be huge error on equivalence point calculations.

Another way to titrate is a strong acid-strong base titration. These titrations involve two strong substances so their reaction yields neutral water, with a pH of 7.00.