Redox Reactions Question 8
Question 8 - 2024 (30 Jan Shift 1)
$2 MnO _4^{-}+bI^{-}+cH _2 O \rightarrow xI _2+yMnO _2+zOH^{-}$
If the above equation is balanced with integer coefficients, the value of $z$ is ________.
Show Answer
Answer (8)
Solution
$ \begin{aligned} \text { Reduction Half} & \quad {\text{Oxidation Half} } \\ \left(2 MnO _4^{-} \rightarrow 2 MnO _2 \right. & \left. \quad 2 I^{-} \rightarrow I _2+2 e^{-}\right) \end{aligned} $
$ \begin{aligned} 2 MnO _4^{-}+4 H _2 O+6 e^{-} \rightarrow 2 MnO _2+8 OH^{-}-6 I^{-} \rightarrow 3 I _2+6 e^{-} \end{aligned} $
Adding oxidation half and reduction half, net reaction is
$2 MnO _4^{-}+6 I^{-}+4 H _2 O \rightarrow 3 I _2+2 MnO _2+8 OH^{-}$
$(\Rightarrow \mathbf{z}=8)$
$\Rightarrow$ Answer 8
