A technician uses a pipette to transfer 25.0 cm325.0\,\mathrm{cm^{3}}25.0cm3 of nitric acid into a conical flask. Potassium hydroxide solution is added from a burette.
At the start of the titration, the jet of the burette contains an air bubble. At the end point, the bubble has gone and the jet is full of potassium hydroxide solution.
| Measurement | Volume in cm3\mathrm{cm^{3}}cm3 |
|---|---|
| Initial burette reading | 1.15 |
| Final burette reading | 26.05 |
| Volume of the air bubble | 0.40 |
Calculate the volume of potassium hydroxide solution that entered the conical flask by the end point.
Show your working.
The technician refills the burette without allowing the jet to empty and titrates a fresh 25.0 cm325.0\,\mathrm{cm^{3}}25.0cm3 sample of the nitric acid.
Explain whether the second recorded titre should be larger than, smaller than or the same as the first recorded titre.
152 exam-style questions on OCR GCSE Chemistry 5.1 Monitoring chemical reactions, covering 5.1.1 The technique of titration, 5.1.2 Theoretical mass, percentage yield and atom economy, 5.1.3 Concentration of a solution in mol/dm3, 5.1.4 Concentration calculations and titration results, 5.1.5 Molar gas volume and volumes of gases in reactions, and 5.1.6 Choosing a reaction pathway. Each one has a worked solution and a mark scheme showing where the marks go.