Required Practical 2: Titration

The procedure for carrying out titration

This is used to find the concentration of an acid

Method:

Example compounds: sulfuric acid + sodium hydroxide —> sodium sulfate + water

• Transfer 25cm³ of sodium hydroxide solution into a conical flask

• Add 5 drops of an indicator phenolphthalein to the flask, turning the solution pink.

• Place a white tile under the flask in order to be able to better see colour changes in the experiment.

• Fill a burette with sulfuric acid and record the starting volume of acid. Make sure you are eye level with the burette when measuring in order to get a clearer reading. Measure from the bottom of the meniscus.

• Add acid to the alkali solution until the solution goes neutral. To do this, add acid until there is a slight colour change, then add it drop by drop until the solution goes colourless (meaning it is neutral). Ensure to swirl the solution to mix the acid and alkali solution better.

• Read the volume of acid and find the difference of the start volume and end volume to find how much acid was used.

• Calculate the concentration of the acid