In: Chemistry
The iodination of acetone, CH3COCH3, in aqueous solution is catalyzed by the hydrogen ion H+:
I2+CH3COCH3H+⟶HI+CH3COCH2I
The reaction can be followed visually by adding starch. The purple starch-iodine complex forms immediately, then disappears when the iodine has been consumed. The kinetics of the reaction may be determined by recording the time required for the color to disappear, which is the time required for the iodine, I2, to be consumed.
The following data were acquired in an iodination experiment involving acetone. All reaction times are in terms of the rate of disappearance of I2.
Trial | Volume of 0.0010 M I2 (mL) |
Volume of 0.050 M HCl (mL) |
Volume of 1.0 Macetone (mL) |
Volume of water (mL) |
Temperature (∘C) |
Reaction time (s) |
A | 5.0 | 10.0 | 10.0 | 25.0 | 25.0 | 130 |
B | 10.0 | 10.0 | 10.0 | 20.0 | 25.0 | 249 |
C | 10.0 | 20.0 | 10.0 | 10.0 | 25.0 | 128 |
D | 10.0 | 10.0 | 20.0 | 10.0 | 25.0 | 131 |
E | 10.0 | 10.0 | 10.0 | 20.0 | 42.4 | 38 |
Calculate: What is the rate constant at 42.4 ∘C based on the data collected for trial E?