Redox Reactions...

Which of the statement is correct?

Which one of the following leads to redox reaction?

The oxidation state of $$Fe$$ in $${ Fe }_{ 3 }{ O }_{ 4 }$$ is

The oxidation state of central atom in the anion of compound $$NaH_2PO_2$$ will be:

Oxidation state of $$Cl$$ in $$CaO{ Cl }_{ 2 }$$ is

Oxidation number of $$'N'$$ in $$N_3H$$ (hydrazoic acid) is:

Oxidation number of carbon in graphite is:

One mole of $$N_{2}H_{4}$$ loses $$10$$ mole of electrons to form a new compound $$Y$$. Assuming that all nitrogen appears in the new compound, what is the oxidation state of $$N$$ and $$Y$$ (there is not change in the oxidation state of hydrogen).

The oxidation states of P atom in $$POCl_3, H_2PO_3$$ and $$H_4P_2O_6$$, respectively are:

In which of the following, the oxidation number of oxygen has been arranged in increasing order?