A student investigated the rate of the reaction between potassium iodide solution and acidified hydrogen peroxide (in the presence of starch indicator) using an iodine clock reaction.
During the method, the student:
Explain why a 100 cm3100\text{ cm}^3100 cm3 beaker is unsuitable to use in this method.
Identify the independent variable and the dependent variable in this investigation.
The table below shows the results of the experiment:
| Concentration of potassium iodide (mol/dm3\text{mol/dm}^3mol/dm3) | Time taken for blue-black color to appear (seconds) |
|---|---|
| 0.05 | 240 |
| 0.10 | 120 |
| 0.15 | 80 |
| 0.20 | 60 |
Which concentration of potassium iodide solution has the highest rate of reaction? Explain how the data shows this.