Chemistry 9701 · AS & A Level · Electrochemistry

Electrochemistry — practice question

Ethanedioic acid, $\text{HO}_2\text{CCO}_2\text{H}$, may be oxidised using $\text{KMnO}_4$ in dilute sulfuric acid. This reaction forms carbon dioxide, water, potassium sulfate and manganese(II) sulfate as products. During this oxidation, each ethanedioic acid molecule gives up two electrons. The half-equation for this change is shown below. $\text{HO}_2\text{CCO}_2\text{H} \rightarrow 2\text{CO}_2 + 2\text{H}^+ + 2e^-$ When five ethanedioic acid molecules are oxidised by $\text{KMnO}_4$ in dilute sulfuric acid, how many water molecules are formed?

  • A5
  • B8
  • C10
  • D16

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