How many electrons are involved in the following redox reaction?\ $\mathrm{Cr}_{2} \mathrm{O}_{7}^{

Question

How many electrons are involved in the following redox reaction?\ $\mathrm{Cr}_{2} \mathrm{O}_{7}^{2-}+\mathrm{Fe}^{2+}+\mathrm{C}_{2} \mathrm{O}_{4}^{2-} ightarrow \mathrm{Cr}^{3+}+\mathrm{Fe}^{3+}+\mathrm{CO}_{2}$\ (Unbalanced)\

Professor PC Thomas Classes · Answer

(c) : $\mathrm{Cr}_{2} \mathrm{O}_{7}{ }^{2-}+\mathrm{Fe}^{2+}+\mathrm{C}_{2} \mathrm{O}_{4}{ }^{2-} \longrightarrow$\ $\mathrm{Cr}^{3+}+\mathrm{Fe}^{3+}+\mathrm{CO}_{2}$\ $\mathrm{Cr}_{2} \mathrm{O}_{7}{ }^{2-}+14 \mathrm{H}^{+}+6 e^{-} \longrightarrow 2 \mathrm{Cr}^{3+}+7 \mathrm{H}_{2} \mathrm{O}$\ $\mathrm{Fe}^{2+} \longrightarrow \mathrm{Fe}^{3+}+e^{-}$\ $4 \mathrm{Fe}^{2+} \longrightarrow 4 \mathrm{Fe}^{3+}+4 e^{-}$\ $\mathrm{C}_{2} \mathrm{O}_{4}^{2-} \longrightarrow 2 \mathrm{CO}_{2}+2 e^{-}$\ Adding equation (i), (iii) and (iv)\ $\mathrm{Cr}_{2} \mathrm{O}_{7}^{2-}+14 \mathrm{H}^{+}+4 \mathrm{Fe}^{2+}+\mathrm{C}_{2} \mathrm{O}_{4}^{2-} \longrightarrow$ $$ 2 \mathrm{Cr}^{3+}+7 \mathrm{H}_{2} \mathrm{O}+4 \mathrm{Fe}^{3+}+2 \mathrm{CO}_{2} $$ Number of electron involved $=6$\