The balanced redox reaction in acidic solution is

CHEMISTRY · Single correct · AP · Chemistry · Chemical Reactions · Chemical Reactions

Problem

Cr_2O_7^{2-}(aq) + 14\,H^{+}(aq) + 6\,I^{-}(aq) \rightarrow 2\,Cr^{3+}(aq) + 3\,I_2(s) + 7\,H_2O(l)

. A student's particulate diagram shows: Reactants:

1\,Cr_2O_7^{2-}

ion,

12\,H^{+}

ions, and

6\,I^{-}

ions. Products:

2\,Cr^{3+}

ions,

3\,I_2

molecules, and

6\,H_2O

molecules. Which modification would make the student's diagram consistent with both mass and charge conservation? (a) Add

1\,H_2O

molecule to the product side. (b) Remove

2\,I^{-}

ions from the reactant side and remove

1\,I_2

molecule from the product side. (c) Add

2\,H^{+}

ions to the reactant side and add

1\,H_2O

molecule to the product side. (d) Add

1\,O^{2-}

ion to the reactant side and add

1\,H^{+}

ion to the product side.