Materials Required

Procedure

Real Lab Procedure

• Take four 250ml conical flasks and label them as A, B, C and D.
• Add 2ml, 4ml, 6ml, and 8ml of 0.01 M potassium iodate (KIO₃) solution to the flasks A, B, C and D.
• Add 10ml of 1M H₂SO₄ to each flask.
• Add water to bring the volume of the solution to 100ml in each flask.
• Add 5ml of starch solution to each flask.
• Add 10ml of 0.005 M sodium sulphite (Na₂SO₃) solution to each flask and start the stop watch immediately.
• Note the time when the blue colour just appears.
• Repeat the above 2 steps with the solutions of flasks B, C and D and note the time required in each case when the blue colour first appears.

Simulator Procedure (as performed through the Online Labs)

• You can select the volume of potassium iodate (KIO₃) solution using the slider.
• Drag the conical flask containing 0.01 M potassium iodate (KIO₃) solution to the measuring jar to measure the solution.
• Drag the measuring jar to the conical flask to pour the solution in it.
• Drag the bottle to the measuring jar to measure 10ml 1 M sulphuric acid.
• Drag the measuring jar to the conical flask to pour sulphuric acid in it.
• Drag the beaker to the measuring jar to measure distilled water.
• Drag the measuring jar to the conical flask to pour water in it.
• Drag the bottle to the measuring jar to measure 5 ml starch solution.
• Drag the measuring jar to the conical flask to pour the starch solution in it.
• Drag the bottle to the measuring jar to measure 10 ml 0.005 M sodium sulphite (Na₂SO₃) solution.
• Drag the measuring jar to the conical flask to pour sodium sulphite solution in it.
• You can get the time taken for the appearance of blue colour from the stopwatch.
• You can use the embedded worksheet to enter the values.
• You can plot a graph using the worksheet.
• To redo the experiment, click the ‘Reset’ button.

Note: Click on the ‘HELP’ button to see the instructions.

Observation

Conclusion

• The rate of reaction increases with increase in concentration of potassium iodate.

Precautions

• Always use a freshly prepared solution of sodium  sulphite because it is easily oxidised by air.
• Concentration of KIO₃ solution should be higher than the concentration of sodium sulphote solution.
• Use a freshly prepared starch solution.