Students investigate the effect of temperature on the rate of reaction between sodium thiosulfate solution and dilute hydrochloric acid. They measure the time taken for a black cross marked on a piece of paper underneath the reaction flask to become obscured by the sulfur precipitate formed (the reaction time) at various temperatures.
The table shows their results:
| Temperature (∘C^\circ\text{C}∘C) | Reaction Time (s\text{s}s) |
|---|---|
| 20 | 120 |
| 30 | 60 |
| 40 | 32 |
| 50 | 18 |
| 60 | 10 |
A student plots these results on a grid and draws a smooth curve of best fit.
a.[1]
Use the curve of best fit to determine the reaction time at 35∘C35^\circ\text{C}35∘C.
b.[1]
State what happens to the rate of reaction as the temperature of the mixture increases.
c.[3]
Explain this change in reaction rate in terms of particle collision theory.