The purpose of this experiment is to determine the rate law for the reaction of iodide ion (I⁻) with bromate ion (BrO₃⁻) in acid solution:
The rate law expression is given by: rate = k [I⁻]x [BrO₃⁻]y [H⁺]z. A starch-thiosulfate clock system is used to measure the rate. Once the constant amount of thiosulfate is consumed, the solution instantly turns blue-black. The relative rate is defined as 1000/t.
| Mixture # | Solution A (mL) | Solution B (mL) | Total Vol (mL) | |||
|---|---|---|---|---|---|---|
| KI (0.0100 M) | Na₂S₂O₃ (0.0010 M) | H₂O | KBrO₃ (0.0400 M) | HCl (0.100 M) | ||
| 1 | 10.00 | 10.00 | 10.00 | 10.00 | 10.00 | 50.00 |
| 2 | 20.00 | 10.00 | 0.00 | 10.00 | 10.00 | 50.00 |
| 3 | 10.00 | 10.00 | 0.00 | 20.00 | 10.00 | 50.00 |
| 4 | 10.00 | 10.00 | 0.00 | 10.00 | 20.00 | 50.00 |
| 5 | 8.00 | 10.00 | 12.00 | 5.00 | 15.00 | 50.00 |
| Parameter Description | Experimental Decimal Value | Rounded Integer Value |
|---|---|---|
| Reactant Exponent x (for I⁻) | — | — |
| Reactant Exponent y (for BrO₃⁻) | — | — |
| Reactant Exponent z (for H⁺) | — | — |
Note: Calculated using standard rounded integers (x = 1, y = 1, z = 2) for standard physical units: M⁻³·s⁻¹.
| Metric Description | Predicted (Calculated) | Observed (Experimental) | Deviation (% Error) |
|---|---|---|---|
| Relative Reaction Rate (1000/t) | — | — | — |
| Reaction Time, t (sec) | — | — |
Enter experimental times for Mixtures 1–4 to calculate reactant exponents.
Rate constant values (k₁ to k₄) should ideally be consistent at a constant temperature.
Compares observed reaction time for Mixture 5 against kinetics prediction.