Chemistry 0620 · IGCSE · Rate of reaction

Rate of reaction — practice question

When aqueous sodium thiosulfate, $\text{Na}_2\text{S}_2\text{O}_3$, is mixed with dilute hydrochloric acid, a yellow sulfur precipitate is produced. $\text{Na}_2\text{S}_2\text{O}_3(\text{aq}) + 2\text{HCl}(\text{aq}) \rightarrow 2\text{NaCl}(\text{aq}) + \text{H}_2\text{O}(\ell) + \text{S}(s) + \text{SO}_2(g)$. The precipitate appears more rapidly when the reactants are heated. Which statements account for this result?

  • A1 and 2
  • B1 and 3
  • C1 only
  • D2 and 3

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