MCQ
$KMn{O_4}$ in basic medium is reduced to
  • A
    ${K_2}Mn{O_4}$
  • $Mn{O_2}$
  • C
    $Mn{(OH)_2}$
  • D
    $M{n^{2 + }}$

Answer

Correct option: B.
$Mn{O_2}$
b
(b)

$KMn{O_4}$ is first reduced to manganate and then to insoluble manganese dioxide. Colour changes first from purple to green and finally becomes colourless.

$2KMn{O_7} + 2KOH \to 2{K_2}Mn{O_4} + {H_2}O + O$

$2{K_2}Mn{O_4} + 2{H_2}O \to 2Mn{O_2} + 4KOH + 2O$

$\overline {2KMn{O_2} + {H_2}O\xrightarrow{{{\text{alkaline}}}}2Mn{O_2} + 2KOH + 3[O]} $

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