Balancing redox equations (half-reaction method) Knowledge-Based Download PDF

Questions

1. 1.

   When the redox equation $\text{Zn}(\text{s}) + \text{NO}_3^-(\text{aq}) \rightarrow \text{Zn}^{2+}(\text{aq}) + \text{NH}_4^+(\text{aq})$ is balanced in an acidic aqueous solution using the half-reaction method with the smallest whole-number coefficients, how many electrons are transferred in the overall reaction?

   • A) 2
   • B) 4
   • C) 6
   • D) 8
2. 2.

   When the redox equation $\text{C}_2\text{O}_4^{2-}(\text{aq}) + \text{MnO}_4^-(\text{aq}) \rightarrow \text{CO}_2(\text{g}) + \text{Mn}^{2+}(\text{aq})$ is balanced in an acidic aqueous solution using the half-reaction method with the smallest whole-number coefficients, what is the sum of all stoichiometric coefficients?

   • A) 33
   • B) 43
   • C) 23
   • D) 20
3. 3.

   When the redox reaction $\text{Cu}(\text{s}) + \text{NO}_3^-(\text{aq}) \rightarrow \text{Cu}^{2+}(\text{aq}) + \text{NO}(\text{g})$ is balanced in an acidic aqueous solution using the half-reaction method with the smallest whole-number coefficients, what is the stoichiometric coefficient of $\text{H}_2\text{O}(\text{l})$?

   • A) 2
   • B) 4
   • C) 6
   • D) 8
4. 4.

   When the redox reaction $\text{MnO}_4^-(\text{aq}) + \text{I}^-(\text{aq}) \rightarrow \text{MnO}_2(\text{s}) + \text{I}_2(\text{s})$ is balanced in a basic aqueous solution using the half-reaction method with the smallest whole-number coefficients, what is the stoichiometric coefficient of $\text{OH}^-(\text{aq})$?

   • A) 4
   • B) 8
   • C) 6
   • D) 2
5. 5.

   When the redox reaction $\text{Cr}_2\text{O}_7^{2-}(\text{aq}) + \text{Fe}^{2+}(\text{aq}) \rightarrow \text{Cr}^{3+}(\text{aq}) + \text{Fe}^{3+}(\text{aq})$ is balanced in an acidic aqueous solution using the half-reaction method with the smallest whole-number coefficients, what is the stoichiometric coefficient of $\text{H}^+(\text{aq})$?

   • A) 14
   • B) 7
   • C) 6
   • D) 8