Which of the following pair will be formed by the decomposition of KMnO₄?

K₂Cr₂O₇ + H₂O₂ + H₂SO₄->  + K₂SO₄ + H₂O compound 'X' is ->CrO₅

Oxidation state of chromium = +6.

Potassium permanganate in alkaline medium oxidise lodide to lodate.

$2Mn{O}_4^{-}+H_{2}O+I^{\Theta }\stackrel{}{\to }2Mn{O}_2+2O{H}^{\Theta }+I{O}_3^{\Theta }(A)$            

Compound A is  . Therefore, oxidation state of 1is + 5.

The colour changes due to change in pH not due to its reaction with water.

Each of the element in group III  to VIIIB  can show the maximum oxidation state equal to its group number.

Mn is in group seven shows a maximum oxidation state of +7 in KMnO₄