Question

Determine the oxidation state for each of the elements below. The oxidation state of ... silver ... in ... silver oxide Ag2O ... is ... ___ . The oxidation state of sulfur in sulfur dioxide SO2 is ___ . The oxidation state of iron in iron(

Answer 1

Answer:

The oxidation state of silver in $\rm Ag_2O$ is $+1$.

The oxidation state of sulfur in $\rm SO_2$ is $+4$.

Explanation:

The oxidation states of atoms in a compound should add up to zero.

Ag₂O

There are two silver $\rm Ag$ atoms and one oxygen $\rm O$ atom in one formula unit of $\rm Ag_2O$. Therefore:

$\begin{aligned}&\rm 2 \times \text{Oxidation state of \rm Ag }+ \rm 1 \times \text{Oxidation state of \rm O } = 0\end{aligned}$.

The oxidation state of oxygen in most compounds (with the exception of peroxides and fluorides) is $-2$. Silver oxide $\rm Ag_2O$ isn't an exception. Therefore:

$\begin{aligned}&\rm 2 \times \text{Oxidation state of \rm Ag }+ \rm 1 \times \text{Oxidation state of \rm O } = 0\\ &\rm 2 \times \text{Oxidation state of \rm Ag }+ \rm 1 \times (-2) = 0\end{aligned}$.

Solve this equation for the (average) oxidation state of $\rm Ag$:

$\text{Oxidation state of \rm Ag } = 1$.

SO₂

Similarly, because there are one sulfur $\rm S$ atom and two oxygen $\rm O$ atoms in each $\rm SO_2$ molecules:

$\begin{aligned}&\rm 1\times \text{Oxidation state of \rm S }+ \rm 2 \times \text{Oxidation state of \rm O } = 0\end{aligned}$.

The oxidation state of $\rm O$ in $\rm SO_2$ is also $-2$, not an exception, either.

Therefore:

$\begin{aligned}&\rm 1 \times \text{Oxidation state of \rm S }+ \rm 2 \times \text{Oxidation state of \rm O } = 0\\ &\rm 1 \times \text{Oxidation state of \rm S }+ \rm 2 \times (-2) = 0\end{aligned}$.

Solve this equation for the oxidation state of $\rm S$ here:

$\text{Oxidation state of \rm S } = 4$.