Investigating the Effect of Temperature on the Reaction Rate between Sodium Thiosulphate and Hydrochloric Acid

This investigation explores how temperature (11.3°C to 37.9°C) affects the reaction rate between 0.1M sodium thiosulfate and 1M hydrochloric acid, measured by the time taken for a marked cross to be obscured by sulfur precipitate.

The methodology involves primary data collection across five temperatures, utilizing an Arrhenius plot (ln(rate) vs. 1/T) to linearize the relationship. Findings reveal a strong exponential correlation (R² = 0.9975), consistent with collision theory and the Arrhenius equation.

The exemplar is distinguished by its rigorous approach to uncertainty, including a benchmark test for human reaction time, preliminary trials to validate the dependent variable, and a detailed evaluation of heat loss and mixing reproducibility.