Question 28
Rates of ReactionThe times taken for iodine to be liberated in the reaction between sodium thiosulphate and hydrochloric acid at various temperature are as follows:
Temp °C: 25, 35, 45
Time (seconds): 72, 36, 18
These results suggest that
- A.for a 10° rise in temperature, rate of reaction is doubled
- B.for a 10° rise in temperature, rate of reaction is halved
- C.time taken for iodine to appear does not depend on temperature
- D.for a 10° rise in temperature, rate of reaction is tripled.
Show the answer and explanation
Answer: A (for a 10° rise in temperature, rate of reaction is doubled)
Explanation
Each 10 °C rise halves the time (72 → 36 → 18 s). Rate is inversely proportional to time, so the rate doubles.