Balancing redox equations (half-reaction method) Knowledge-Based Practice

Questions

1. 1.

   When the disproportionation reaction $\text{Cl}_2(\text{g}) \rightarrow \text{Cl}^-(\text{aq}) + \text{ClO}_3^-(\text{aq})$ is balanced in basic aqueous solution using the smallest whole-number coefficients, what is the stoichiometric coefficient of $\text{Cl}_2(\text{g})$?

   • A) 1
   • B) 3
   • C) 5
   • D) 6
2. 2.

   When the oxidation–reduction reaction $\text{MnO}_4^-(\text{aq}) + \text{C}_2\text{O}_4^{2-}(\text{aq}) \rightarrow \text{Mn}^{2+}(\text{aq}) + \text{CO}_2(\text{g})$ is balanced in acidic aqueous solution using the smallest whole-number coefficients, what is the total number of electrons transferred?

   • A) 10
   • B) 5
   • C) 7
   • D) 2
3. 3.

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

   • A) 4
   • B) 2
   • C) 3
   • D) 8
4. 4.

   When the oxidation–reduction reaction $\text{MnO}_4^-(\text{aq}) + \text{SO}_3^{2-}(\text{aq}) \rightarrow \text{MnO}_2(\text{s}) + \text{SO}_4^{2-}(\text{aq})$ is balanced in basic aqueous solution using the smallest whole-number coefficients, what is the stoichiometric coefficient of $\text{OH}^-(\text{aq})$?

   • A) 1
   • B) 2
   • C) 4
   • D) 6
5. 5.

   When the oxidation–reduction reaction $\text{Cr}_2\text{O}_7^{2-} + \text{Fe}^{2+} \rightarrow \text{Cr}^{3+} + \text{Fe}^{3+}$ is balanced in an acidic solution using smallest whole-number coefficients, what is the coefficient of $\text{H}^+$?

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

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