Respuesta :
Explanation:
In a chemical reaction equation, if number of atoms on the reactant side are equal to the number of atoms on product side then it is known as a balanced equation.
And, a redox reaction is defined as the reaction where there occurs change in the oxidation states of the reactants.
For example, [tex]MnO^{-}_{4}(aq) + SO^{2-}_{3}(aq) + H_{3}O^{+}(aq) \rightarrow Mn^{2+}(aq) + SO^{2-}_{4}(aq) + H_{2}O(l)[/tex]
Reduction-half reaction: [tex]8H_{3}O^{+} + MnO^{-}_{4} + 5e^{-} \rightarrow Mn^{2+} + 12H_{2}O[/tex] ....... (1)
Oxidation-half reaction: [tex]SO^{2-}_{3} + 3H_{2}O \rightarrow SO^{2-}_{4} + 2e^{-} + 2H_{3}O^{+}[/tex] ............. (2)
Now, we multiply equation (1) by 2 and multiply equation (2) by 5.
[tex]16H_{3}O^{+} + 2MnO^{-}_{4} + 10e^{-} \rightarrow 2Mn^{2+} + 24H_{2}O[/tex] ......... (3)
[tex]5SO^{2-}_{3} + 15H_{2}O \rightarrow 5SO^{2-}_{4} + 10e^{-} + 10H_{3}O^{+}[/tex] ......... (4)
Now, add both of equations (3) and (4) and the balance equation will be as follows.
[tex]2MnO^{-}_{4}(aq) + 5SO^{2-}_{3}(aq) + 6H_{3}O^{+}(aq) \rightarrow 2Mn^{2+}(aq) + 5SO^{2-}_{4}(aq) + 9H_{2}O(l)[/tex]
Hence, the coefficient of [tex]H_{2}O[/tex] is 9.
