required practical 1B

• 1. pour approximately 100cm3 of NaHSO4 made in part A into a clean, dry beaker that is labelled 'NaHSO4' - use a small volume of this solution to rinse the burette before filling it with the NaHSO4 solution
• 2. pour approximately 100cm3 of the NaOH solution into a second clean, dry beaker labelled 'NaOH'
• 3. choose an appropriate piece of equipment to accurately transfer 25cm3 of the NaOH solution into a clean 100cm3 conical flask
• 4. add 2-3 drops of phenolphthalein indicator to the solution in the conical flask and note the colour of the indicator in alkali. Before you start to titrate, construct a table ready to record your results
• 5. record the initial burette reading - make sure that all your burette readings are to the appropriate precision
• 6. titrate the contents of the conical flask by adding NaHSO4 solution to it from the burette. Add the NaHSO4 slowly, swirling the flask gently to mix the solution. If any of the contents of the flask get splashed up the sides, use a wash bottle containing distilled water to rinse the drops back into the solution
• 7. add the NaHSO4 solution dropwise near the end-point until the indicator undergoes a definite colour change; this is the end-point of the titration. Record the colour change in your results. Record the final burette reading in the table of results
• 8. calculate and record the table of results the volume of NaHSO4 solution used
• 9. repeat the titration until you obtain 2 results, which are concordant. You should normally carry out at least 3 titrations. Record all the results that you obtain
• 10. calculate and record the mean volume of NaHSO4 solution used in the titration and show working