Q. What is the oxidation number of Mn in $K_{2} M n O_{4}$ ?

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A

$+ 5$

3%

B

$+ 6$

70%

C

$+ 7$

14%

D

$+ 4$

13%

Solution:

Let the oxidation no. of $M n$ be $x$ .
$K_{2} M n O_{4}$
$\Rightarrow 2 + x + 4 (- 2) = 0$
$2 + x - 8 = 0$
$\Rightarrow x = + 6$