Redox Reactions...

The oxidation number of all the elements in the given compound is:    Ethane ($${ C }_{ 2 }{ H }_{ 6 }$$)

Of the following acids, the one that is strongest is :

For a titration of $$100\: {cm}^{3}$$ of $$0.1$$ $$M$$ $${ Sn }^{ 2+ }$$ to $${ Sn }^{ 4+ }$$, $$50$$ $${cm}^{3}$$ of $$0.40$$ $$M$$ $${ Ce }^{ 4+ }$$ solution was required. The oxidation state of cerium in the reduction product is :

Oxidation number of $$Cr$$ in the following compounds are $$x,y,z$$ and $$w$$ respectively.
$$K\left[ \underset { x }{ Cr } O({ O }_{ 2 })(OH) \right] ,\quad { K }_{ 3 }\left[ \underset { y }{ Cr } { \left( { O }_{ 2 } \right)  }_{ 4 } \right] ,\quad { \left( { NH }_{ 3 } \right)  }_{ 3 }\left[ \underset { z }{ Cr } { \left( { O }_{ 2 } \right)  }_{ 2 } \right] ,\quad \underset { w }{ Cr } { O }_{ 2 }{ Cl }_{ 2 }$$
These values are, respectively :

Oxidation number of $$Cr$$ is $$+5$$ in :

Consider the following unbalanced reactions:
$$I: Zn+dil.\:{ H }_{ 2 }S{ O }_{ 4 }\longrightarrow ZnS{ O }_{ 4 }+{ H }_{ 2 }$$
$$II: Zn+conc.\:{ H }_{ 2 }S{ O }_{ 4 }\longrightarrow ZnS{ O }_{ 4 }+S{ O }_{ 2 }+{ H }_{ 2 }O\quad $$
$$III: Zn+HN{ O }_{ 3 }\longrightarrow Zn{ \left( { NO }_{ 3 } \right)  }_{ 2 }+{ NH }_{ 4 }{ NO }_{ 3 }+{ H }_{ 2 }O$$
Oxidation number of hydrogen changes in :

Out of $$\underset { (I) }{ { H }_{ 2 }S{ O }_{ 4 } } ,\ \underset { (II) }{ { H }_{ 2 }{ S }_{ 2 }{ O }_{ 7 } } ,\ \underset { (III) }{ { H }_{ 2 }S{ O }_{ 5 } }$$ and $$\underset { (IV) }{ { H }_{ 2 }{ S }_{ 2 }{ O }_{ 3 } } $$ :

In the presence of $$SO_3^{\displaystyle2-}$$ and $$S^{\displaystyle2-}$$ in a mixture, on adding $$dil.\:H_2SO_4$$, one notices :

$$Mn{O}_{4}^{2-}$$ (1 mole) in neutral aqueous medium disproportionate to :

Compound(s) of $$Cu$$ and $$Ag$$ showing $$+3$$ oxidation state is\are :