Consider the following redox equation When the equation is balanced with smallest whole number coefficients, what is the coefficient for OH¯(aq) and on which side of the equation is OH¯(aq) present?

Question

Consider the following redox equation  When the equation is balanced with smallest whole number coefficients, what is the coefficient for OH¯(aq) and on which side of the equation is OH¯(aq) present?

Quizplus · Accepted Answer

The presence of OH¯(aq) indicates that the reaction is taking place in basic solution. To balance the equation in basic solution, we first balance the equation as if it were in acidic solution. This gives us:

$11	ext{FeSO}_4 + 	ext{Ce(SO}_4	ext{)}_{2} + 7	ext{H}_2	ext{SO}_4 ightarrow 5	ext{Fe}\left(	ext{SO}_4ight)_{3} + 11	ext{H}_2	ext{O} + 	ext{Ce}\left(	ext{SO}_4ight)_{2}$

Then, we add one OH¯(aq) ion to each side of the equation for each H+ ion:

$11	ext{FeSO}_4 + 	ext{Ce(SO}_4	ext{)}_{2} + 7	ext{H}_2	ext{SO}_4 + 22	ext{OH}^- ightarrow 5	ext{Fe}\left(	ext{SO}_4ight)_{3} + 11	ext{H}_2	ext{O} + 	ext{Ce}\left(	ext{SO}_4ight)_{2} + 22	ext{OH}^-$

Simplifying the equation by cancelling out the OH¯(aq) ions gives:

$11	ext{FeSO}_4 + 	ext{Ce(SO}_4	ext{)}_{2} + 7	ext{H}_2	ext{O} ightarrow 5	ext{Fe}\left(	ext{SO}_4ight)_{3} + 11	ext{H}_2	ext{O} + 	ext{Ce}\left(	ext{SO}_4ight)_{2}$
The coefficient for OH¯(aq) is 6 and it is present on the reactant side. Therefore, the answer is (C).

Consider the Following Redox Equation When the Equation Is