A titration measures the volume that reacts completely

1. Titrations are most often used for neutralisation reactions between an acid and an alkali.
2. A fixed volume of one solution, often the alkali, is measured into a conical flask.
3. The other solution is added gradually from a burette until the reaction is complete.
4. A few drops of indicator in the flask change colour when neutralisation is complete.
   1. The volume added from the burette to reach this point is called the titre.
5. If the concentration of one solution is known, the titre can later be used to work out the unknown concentration of the other.

Pipettes measure fixed volumes and burettes measure variable volumes

1. Rinse the pipette with a little of the solution it will measure, so that no water is left inside to dilute it.
2. Use a pipette filler to draw the solution up until the bottom of the meniscus sits on the line, reading it at eye level.
   1. Let the solution run into the conical flask and touch the tip on the inside of the flask, but do not blow out the last drop.
3. Rinse the burette with the solution it will hold, then fill it using a small funnel and remove the funnel before reading it.
4. Open the tap briefly so that the jet below the tap fills and contains no air bubble.
5. Read the burette at eye level from the bottom of the meniscus, recording each reading to the nearest $0.05{cm}^3$.
   1. Readings are written to two decimal places, so a reading halfway between $22.40$ and $22.50$ is recorded as $22.45{cm}^3$.

An indicator's sharp colour change shows the end point

1. Add only a few drops of indicator, because the indicator is itself a weak acid and too much can affect the result.
2. Phenolphthalein is colourless in acid and pink in alkali.
3. Methyl orange is red in acid and yellow in alkali.
4. The colour change you see depends on which solution starts in the flask, so describe it in the direction the titration runs.
   1. With alkali in the flask and acid in the burette, phenolphthalein turns from pink to colourless and methyl orange turns from yellow to red.
5. Universal indicator is not used, because it changes colour gradually through many shades instead of at one sharp point.
6. Standing the flask on a white tile makes the colour change easier to see.

A rough titration comes before accurate dropwise titrations

1. The first rough titration adds the solution quickly while swirling, to find roughly where the end point is.
2. In each accurate titration, add the solution quickly until you are about $2{cm}^3$ short of the rough titre.
   1. Then add it drop by drop, swirling after each drop, so that you do not overshoot the end point.
3. Wash any drops on the inside of the flask down with a little distilled water, so all the solution added can react.
4. Stop at the first permanent colour change and record the final burette reading.
5. Calculate the titre by subtracting the initial burette reading from the final reading.

Concordant titres are averaged to give a reliable titre

1. Repeat the accurate titration until at least two titres are concordant, which usually means within $0.10{cm}^3$ of each other.
2. Leave the rough titre out of the mean, because the solution was added too quickly for it to be accurate.
3. Also leave out any anomalous titre, such as one where the end point was overshot.
4. Calculate the mean titre from the concordant results only.
5. Concordant results show that the method is repeatable, so the mean titre is a trustworthy value.