question_answer

For the redox reaction\[\text{MnO}_{4}^{-}+{{C}_{2}}O_{4}^{2-}+{{H}^{+}}\xrightarrow{{}}M{{n}^{2+}}+C{{O}_{2}}+{{H}_{2}}O\]. The correct coefficients of the reactants for the balanced equation are                 [NEET - 2018]

A)

\[\text{MnO}_{\text{4}}^{\text{-}}\]	\[{{\text{C}}_{\text{2}}}\text{O}_{\text{4}}^{\text{2-}}\]	\[{{\text{H}}^{+}}\]
2	16	5

B)

\[\text{MnO}_{\text{4}}^{\text{-}}\]	\[{{\text{C}}_{\text{2}}}\text{O}_{\text{4}}^{\text{2-}}\]	\[{{\text{H}}^{+}}\]
2	5	16

C)

\[\text{MnO}_{\text{4}}^{\text{-}}\]	\[{{\text{C}}_{\text{2}}}\text{O}_{\text{4}}^{\text{2-}}\]	\[{{\text{H}}^{+}}\]
16	5	2

D)

\[\text{MnO}_{\text{4}}^{\text{-}}\]	\[{{\text{C}}_{\text{2}}}\text{O}_{\text{4}}^{\text{2-}}\]	\[{{\text{H}}^{+}}\]
5	16	2

Correct Answer: B

Solution :

n-factor of \[\text{MnO}_{4}^{-}\Rightarrow 5\] n-factor of \[{{C}_{2}}O_{4}^{2-}\Rightarrow 2\] Ratio of n-factors of \[\text{MnO}_{\text{4}}^{\text{-}}\] and \[{{\text{C}}_{\text{2}}}\text{O}_{\text{4}}^{\text{2-}}\] is \[\text{5:2}\]So, molar ratio in balanced reaction is \[2:5\] \[\therefore \] The balanced equation is \[\text{2MnO}_{\text{4}}^{\text{-}}\text{+5}{{\text{C}}_{\text{2}}}\text{O}_{\text{4}}^{\text{2-}}\text{+16}{{\text{H}}^{\text{+}}}\to \text{2M}{{\text{n}}^{\text{2+}}}\text{+10C}{{\text{O}}_{\text{2}}}\text{+8}{{\text{H}}_{\text{2}}}\text{O}\]