When `K_2 Cr_2 O_7` is converted to `K_2 CrO_4` then change in the oxidation state of chromium is :

The oxidation state of Cr is K_3CrO_8

What is the oxidation state of K in KO_2 ?

K_2Cr_2O_7 cannot be used for

In the preparation of KMnO4, pyrolusite (MnO_(2)) is first converted to potassium magnate (K_(2)MnO_(4)) . In this conversion, the oxidation state of manganese changes from

(A) Mn _(2) O _(7) and Cr O _(3) are acidic oxides. (R ) In Mn _(2) O _(7)and CrO _(3) the Mn and Cr are in their highest oxidation states.

Calculate the oxidation number of 'Cr' in K_2Cr_2O_2 .