Redox Reactions...

The oxidation number of Cr is +6 in:

The oxidation number of Cl in $$Ca(ClO_{2})_{2}$$:

Oxidation number of $$Fe$$ in $$Fe_{3}O_{4}$$ is:

The order of the oxidation state of the phosphorus atom in $$ H_{3}PO_{2} $$, $$ H_{3}PO_{4} $$, $$ H_{3}PO_{3} $$ and $$ H_{4}P_{2}O_{6} $$

The oxidation states  of $$Cr$$ in $$ \left [ Cr\left (H_{2}O_{6}  \right ) \right ]Cl_{3} $$, $$ \left [ Cr\left (C_{6} H_{6} \right )_{2} \right ] $$ and $$ K_{2}\left [ Cr\left (CN_{2}  \right ) \left ( O_{2} \right )\left ( O_{2} \right )\left ( NH_{3} \right ) \right] $$ respectively are

The oxidation states of Cr in  $$  \left [Cr(H_{2}O_{6})  \right ] Cl_{3} $$, $$ \left [ Cr(C_{6}H_{6})_{2} \right ] $$ and $$ K_{2}\left [ Cr(CN)_{2}(O_{2})(O_{2})(NH_{3}) \right ] $$ respectively are

Which of the following reaction is an example of redox reactions

In which of the following reactions, there is no change valency ?

Oxidation number of $$N$$ in $${({NH}_{4})}_{2}{SO}_{4}$$ is

The oxidation numbers of $$S$$ in $$S_{8},\ S_{2}F_{2}$$ and $$H_{2}S$$ respectively are