Chemistry 0620 · IGCSE · Rate of reaction

Rate of reaction — practice question

Marble chips (calcium carbonate) undergo reaction with hydrochloric acid in an exothermic reaction. $\text{calcium carbonate} + \text{hydrochloric acid} \rightarrow \text{calcium chloride} + \text{water} + \text{carbon dioxide}$ If excess marble chips are placed into dilute hydrochloric acid, the reaction begins rapidly, then becomes slower until it comes to a stop. Why does the reaction rate become slower?

  • AThe concentration of the hydrochloric acid is decreasing.
  • BThe concentration of calcium chloride is increasing.
  • CThe calcium carbonate is completely used up.
  • DThe temperature of the mixture decreases.

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