TItration

• Titration is a laboratory technique used to determine the concentration of an unknown acid or base. The process involves gradually adding a solution of known concentration, the titrant, to a solution of unknown concentration.

• The point at which all the acid or base has reacted in the solution is called the equivalence point. The volume of titrant required to reach this point can be used to calculate the concentration of the unknown solution.

• In an acid-base titration, the titrant and the substance it is reacting with will often be colourless. To visualise the equivalence point, a pH indicator is added. This changes colour when the solution switches from being acidic to alkaline, or vice versa.

• The choice of indicator depends on the specific nature of the reaction. For example, phenolphthalein turns from colourless to pink as the solution changes from acidic to slightly alkaline, making it ideal for strong acid/weak alkali titrations.

• Universal indicator can also be used in titrations. It changes colour over a range of pH values and can show the approximate pH of the solution.

• Concentration of the unknown solution can be calculated using the formula: C1V1 = C2V2. Where C1 is the concentration of the known solution, V1 is the volume of the known solution, C2 is the concentration of the unknown solution, and V2 is the volume of the unknown solution.

• It’s important to always perform more than one titration for accuracy, discarding the initial ‘rough’ titration and then taking an average from the ‘fair’ titrations.

• Ensuring correct technique is crucial. The burette should be read at eye level, and the bottom of the meniscus should align with the calibration mark. Small increments should be added near the end point to avoid overshooting the equivalence point.

• Remember safety precautions, as the substances used in titrations can often be corrosive. Always use appropriate safety gear, including gloves and eye protection.