Oxidation Number

The oxidation state of Cr in  ${[\text{Cr}{({\text{NH}}_{\text{3}})}_{\text{4}}{\text{Cl}}_{\text{2}}]}^{+}$  is

Oxidation number of iodine varies from

Which of the following oxidation states is/are shown by hydrogen?

One mole of hydrazine $\left(N_2{H}_4\right)$ loses 10 moles of electrons in a reaction to form a new compound $X.$ Assuming that all the nitrogen atoms in hydrazine appear in the new compound, what is the oxidation state of nitrogen in $X$ ? (Note There is no change in the oxidation state of hydrogen in the reaction)

Which of the following oxidation states is/are shown by hydrogen?

What is the oxidation state of $\mathrm{I}$ in ${\mathrm{INO}}_3$?

What is the oxidation number of copper in brass?

The oxidation state of nitrogen in dinitrogen trioxide is:

The heating of ${\left({\mathrm{NH}}_4\right)}_2{\mathrm{Cr}}_2{\mathrm{O}}_7$ produces another chromium compound along with ${\mathrm{N}}_2$ gas. The change of the oxidation state of $\mathrm{Cr}$ in the reaction is

The formal oxidation numbers of $\text{C}\text{r}$ and $\text{C}\text{l}$ in the ions ${\mathrm{Cr}}_2{\mathrm{O}}_7^{2-}$ and $\text{C}\text{l}{\text{O}}_3^{-}$, respectively are

The sum of oxidation number of all the atoms in ${\mathrm{S}}_2{\mathrm{O}}_3^{2-}$ ion is

The oxidation states of $\mathrm{S}$ in ${\mathrm{H}}_2 {\mathrm{S}}_2{\mathrm{O}}_7$ are:

How many of the following species have formal oxidation state of $\mathrm{N}$ or $\mathrm{P}$ as $\text{'}+5\text{'}$

${\mathrm{N}}_2{\mathrm{O}}_5, {\mathrm{NO}}_3^{-}, {\mathrm{NO}}_2^{-}, {\left[{\mathrm{PO}}_4\right]}^{3-}, {\mathrm{P}}_4{\mathrm{O}}_6, {\mathrm{P}}_4{\mathrm{O}}_{10}, {\mathrm{H}}_3{\mathrm{PO}}_3$

The oxidation number of an element in a compound is evaluated on the basis of certain rules. Which of the following rules is not correct?

A. The oxidation number of hydrogen is always $+1$.

B. The algebraic sum of all the oxidation numbers of all elements in a compound is zero.

C. An element in the free or the uncombined state bears the oxidation number zero.

D. In all its compounds, the oxidation number of fluorine is $-1$.

How much charge is required for the oxidation of $1$ mole of ${\mathrm{S}}_2{\mathrm{O}}_3^{-2}$ to ${\mathrm{S}}_4{\mathrm{O}}_6^{-2}?$

How many moles of ${\mathrm{KMnO}}_4$ are reduced by $1 \mathrm{mole}$ of ferrous oxalate in acidic medium:-

The species with an atom in $+6$ oxidation state is

$\mathrm{Ca}(\mathrm{OH}{)}_2+{\mathrm{Cl}}_2\to \mathrm{X}+\mathrm{Ca}{\left(\mathrm{OCl}\right)}_2+{\mathrm{H}}_2\mathrm{O}$
Oxidation state of $\mathrm{Cl}$ in X is

Sulphur and rest of the elements of group 16 are less electronegative than oxygen. Therefore, their atoms cannot take up electrons easily. They can acquire ns²np⁶ configuration by sharing two electrons with the atoms of other elements and thus, exhibit +2 oxidation state in their compounds. In addition to this, their atoms have vacant d-orbitals in their valence shell to which electrons can be promoted from the p and s-orbitals of the same shell. As a result, they can show +4 and +6 oxidation states.

Like sulphur, oxygen does not show +4 and +6 oxidation states. The reason is :