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Q.
The metal with the highest oxidation state present in
$K_2CrO_4, NbCl_5$ and $MnO_2$ is
KVPYKVPY 2014Redox Reactions
Solution:
Let the oxidation state of metals in given compounds be $x$.
(i) $K_2CrO_4$
$2\left(+1\right)+x+4\left(-2\right)=0$
$x=8-2=+6$
The oxidation state of $K$ is $K_{2}CrO_{4} is + 6$.
(ii)$NbCl_{5}$
$x+5\left(-1\right)=0$
$x=+5$
Oxidation state of $Nb$ in $NbCl_{5}$ is $+5$.
(iii)$MnO_{2}$
$x+2\left(-2\right)=0$
$x=+4$
Oxidation state of $Mn$ is $MnO_{2}$ is +4.
Thus, $Cr$ has the highest oxidation state $(+6)$ among the given metals.