Medium INTEGER +4 / -1 PYQ · JEE Mains 2024

$$2 \mathrm{MnO}_4^{-}+\mathrm{bI}^{-}+\mathrm{cH}_2 \mathrm{O} \rightarrow x \mathrm{I}_2+y \mathrm{MnO}_2+z \overline{\mathrm{O}} \mathrm{H}$$

If the above equation is balanced with integer coefficients, the value of $z$ is ________.

Answer (integer) 8

Solution

<p><style type="text/css"> .tg {border-collapse:collapse;border-spacing:0;} .tg td{border-color:black;border-style:solid;border-width:1px;font-family:Arial, sans-serif;font-size:14px; overflow:hidden;padding:10px 5px;word-break:normal;} .tg th{border-color:black;border-style:solid;border-width:1px;font-family:Arial, sans-serif;font-size:14px; font-weight:normal;overflow:hidden;padding:10px 5px;word-break:normal;} .tg .tg-baqh{text-align:center;vertical-align:top} .tg .tg-amwm{font-weight:bold;text-align:center;vertical-align:top} </style> <table class="tg" style="undefined;table-layout: fixed; width: 600px"> <colgroup> <col style="width: 337px"> <col style="width: 263px"> </colgroup> <thead> <tr> <th class="tg-amwm">Reduction Half</th> <th class="tg-amwm">Oxidation Half</th> </tr> </thead> <tbody> <tr> <td class="tg-baqh">$2 \mathrm{MnO}_4^{-} \rightarrow 2 \mathrm{MnO}_2$</td> <td class="tg-baqh">$2 \mathrm{I}^{-} \rightarrow \mathrm{I}_2+2 \mathrm{e}^{-}$</td> </tr> <tr> <td class="tg-baqh">$$2 \mathrm{MnO}_4^{-}+4 \mathrm{H}_2 \mathrm{O}+6 \mathrm{e}^{-} \rightarrow 2 \mathrm{MnO}_2+8 \mathrm{OH}^{-}$$</td> <td class="tg-baqh">$6 \mathrm{I}^{-} \rightarrow 3 \mathrm{I}_2+6 \mathrm{e}^{-}$</td> </tr> </tbody> </table></p> <p>Adding oxidation half and reduction half, net reaction is</p> <p>$$\begin{aligned} & 2 \mathrm{MnO}_4^{-}+6 \mathrm{I}^{-}+4 \mathrm{H}_2 \mathrm{O} \rightarrow 3 \mathrm{I}_2+2 \mathrm{MnO}_2+8 \mathrm{OH}^{-} \\ \Rightarrow \quad & \mathrm{z}=8 \\ \Rightarrow \quad & \text { Ans } 8 \end{aligned}$$</p>

About this question

Subject: Chemistry · Chapter: Redox Reactions · Topic: Oxidation States

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