Procedure

1. Select the weight of aspirin from the slider.
2. Click on the “Add aspirin” button to take aspirin in the R.B. flask.
3. Click on the “Add NaOH” button to add 40 mL of 10% NaOH.
4. Click on the “Next” button.
5. Click on the “Reflux” button to reflux the content for 15 minutes.
6. Click “Next”.
7. Click “Transfer solution” button to transfer it into a 250 mL standard flask.
8. Click “Make up solution” button to make up the solution up to the mark.
9. Click “Next”.
10. Select the volume of aspirin.
11. Click “Pipette out” button to pipette out the aspirin.
12. Click on the “box” in front of “Preparation of titrate” to view the procedure after selecting the volume.
13. Click “Next”.
14. Select the titrant (sodium thiosulphate).
15. Adjust the speed of drops.
16. Click on the “Start” button to start titration.
17. Near the end point, when the colour just fades, click on the “Add Starch” button to add the indicator.
18. Adjust the speed of drops.
19. Click on the “Start” button to continue the titration.
20. When the blue colour disappears, click on the “Stop” button to stop the titration.

Note: Here, 50 mL brominating mixture (Blank) = 45.6 mL thiosulphate.