In acidic medium, H₂O₂ changes Cr₂O₇^2- to CrO₅ which has two

($$-$$O$$-$$O$$-$$) bonds. Oxidation state of Cr in CrO₅ is

When Cl₂ gas reacts with hot and concentrated sodium hydroxide solution, the oxidation number of chlorine changes from

A mixture of potassium chlorate, oxalic acid and sulphuric acid is heated. During the reaction which element undergoes maximum change in the oxidation number?

Oxidation numbers of P in PO$$_4^{3 - }$$, of S in SO$$_4^{2 - }$$ and that of Cr in Cr₂O$$_7^{2 - }$$ are respectively