Redox Reactions...

The oxidation number of oxygen in $$K{ O }_{ 3 },{ Na }_{ 2 }{ O }_{ 2 }$$ is:

In view of the signs of $$\triangle_{r}G^{\circ}$$ for the following reactions
$$PbO_{2} + Pb \rightarrow 2PbO, \triangle_{r}G^{\circ} < 0$$,
$$SnO_{2} + Sn \rightarrow 2SnO, \triangle G^{\circ} > 0$$
Which oxidation states are more characteristic for lead and tin?

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

In the conversion of $$Br_2$$ to $$Br{ O }^{-}_{3}$$ the oxidation state of bromine changes from:

Consider the following half-cell reactions and associated standard half-cell potentials and determine the maximum voltage that can be obtained by combination resulting in spontaneous processes:
$$AuBr_{4}^{-}(aq) + 3e^{-} \rightarrow Au(s) + 4Br^{-}(aq); E^{\circ} = -0.86\ V$$
$$Eu^{3+}(aq) + e^{-} \rightarrow Eu^{2+}(aq); E^{\circ} = -0.43\ V$$
$$Sn^{2+}(aq) + 2e^{-} \rightarrow Sn(s); E^{\circ} = -0.14\ V$$
$$IO^{-}(aq) + H_{2}O(l) + 2e^{-}\rightarrow I^{-}(aq) + 2OH^{-}(aq); E^{\circ} = + 0.49\ V$$

What is the oxidation number of tungsten in the ion $$W_6O_6Cl^{2-}_{12}$$ ? 

$$CH_3COOH$$ is neutralized by $$NaOH$$. Conductometric titration curve will be of the type: 

The oxidation numbers of the sulphur atoms in peroxomonosulphuric acid $$(H_{2}SO_{5})$$ and peroxodisulphuric acid $$(H_{2}S_{2}O_{8})$$ are respectively

Oxidation numbers of $$Mn$$ in its compounds $$ MnCl_2$$ , $$ Mn(OH)_3$$, $$MnO_2$$ and $$ KMnO_4 $$ respectively are:

The oxidation state of sulphur in the anions $$ { SO }_{ 3 }^{ 2- },{ SO }_{ 4 }^{ 2- },S_2{ O }_{ 4 }^{ 2- },S_2{ O }_{ 6 }^{ 2- } $$ is in the order :