Question

Hydrogen peroxide oxidises $\left[Fe\right(CN{)}_6{]}^{4-}$ to $\left[Fe\right(CN{)}_6{]}^{3-}$ in acidic medium but reduce $\left[Fe\right(CN{)}_6{]}^{3-}$ to $\left[Fe\right(CN{)}_6{]}^{4-}$ in alkaline medium. The other products formed are, respectively:

• A. $H_{2}O$ and $(H_{2}O+O{H}^{-})$
• B. $H_{2}O$ and $(H_{2}O+O_2)$
• C. $(H_{2}O+O_2)$ and $H_{2}O$
• D. $(H_{2}O+O_2)$ and $(H_{2}O+O{H}^{-})$

Answer 1

Answer: (B)

(i) $\left[F{e}^{+2}\right(CN{)}_6{]}^{4-}+H_2{O}_2+2H^{+}\to \left[F{e}^{+3}\right(CN{)}_6{]}^{3-}+2H_{2}O$

(ii) $\left[F{e}^{+3}\right(CN{)}_6{]}^{3-}+H_2{O}_2+2O{H}^{-}\to \left[F{e}^{+2}\right(CN{)}_6{]}^{4-}+O_2+2H_{2}O$