Chromatography is a technique used to separate the components present within a mixture.

Chromatography separates substances by making use of differences in their polarity or molecular size.

Depending on the type of chromatography used, the identity of a component can be indicated either by the distance it has travelled, or by the time it has taken to travel through the apparatus — the retention time, $R_t$.

The results of a chromatography experiment can sometimes be presented graphically, showing an indication of the quantity of substance present on the y-axis and retention time of the x-axis.

Sometimes the volume of a solution needed is too large to fit on a scale and be adequately analysed.

In this case the solution should be diluted — the solution which is not being investigated should be diluted, so that the calculated concentration still gives the correct information on the other solution.

Sometimes it can be hard to tell retention time because two peaks overlap.

Volumetric analysis involves using a solution of accurately known concentration in a quantitative reaction to determine the concentration of another substance.

Titration is used to determine, accurately, the volumes of solution required to reach the end-point of a chemical reaction.

An indicator is normally used to show when the end-point is reached in a titration.

Titre volumes within 0·2 $cm^3$ are considered concordant.

Solutions of accurately known concentration are known as standard solutions.

Redox titrations are based on redox reactions.

In titrations using acidified permanganate, an indicator is not required, as purple permanganate solution turns colourless when reduced.

In redox titrations, an acid is added to provide the $H^+$ ions needed to complete the redox reaction.

Given a balanced equation for the reaction occurring in any titration, the concentration of one reactant can be calculated given the concentration of the other reactant and the volumes of both solutions, and the volume of one reactant can be calculated given the volume of the other reactant and the concentrations of both solutions.