Investigation: preparation of a standard solution and titration

Aim: to prepare a standard solution accurately and use it to determine the concentration of an unknown acid.

• Apparatus: volumetric flask, pipette, burette, conical flask, indicator.
• Method: dissolve a weighed mass, make up to the mark, then titrate against the unknown to a colour change.
• Repeat until concordant titres (within 0,1 cm³) are obtained, then average them.
• Calculate with n = cV and the mole ratio from the balanced equation.

• Standard solution — accurately known concentration.
• Endpoint — where the indicator changes colour permanently.