Question

In which of the following compounds does the sulfur atom have different oxidation numbers?
(a)- ${{H}_{2}}S{{O}_{4}}$
(b)- $HSO_{3}^{-}$
(c)- $S{{O}_{2}}C{{l}_{2}}$
(d)- $S{{O}_{3}}$

Answer 1

To calculate the oxidation state of sulfur in the compounds in the question, take the oxidation state of oxygen -2, take the oxidation state of hydrogen +1, and take the oxidation state of halogens -1.

Complete step by step solution:
Oxidation state or oxidation number is the number that tells the combined state of the particular elements with other elements in the compounds. The oxidation number or oxidation state can be positive, negative, and even zero.
To calculate the oxidation state of sulfur in the compounds in the question, take the oxidation state of oxygen -2, take the oxidation state of hydrogen +1, and take the oxidation state of halogens -1.
So, the oxidation state of sulfur in ${{H}_{2}}S{{O}_{4}}$, is calculated as follows by taking the oxidation state of hydrogen and oxygen as +1 and -2 respectively:
$2(+1)+x+4(-2)=0$
$2+x-8=0$
$x-6=0$
$x=+6$
The oxidation state is +6.

- The oxidation state of sulfur in $HSO_{3}^{-}$, is calculated as follows by taking the oxidation state of hydrogen and oxygen as +1 and -2 respectively:
$+1+x+3(-2)=-1$
$1+x-6=-1$
$x-5=-1$
$x=-1+5$
$x=+4$
So, the oxidation state of sulfur is +4.

- The oxidation state of sulfur in $S{{O}_{2}}C{{l}_{2}}$, is calculated as follows by taking the oxidation state of oxygen and chlorine as -2 and -1 respectively:
$x+2(-2)+2(-1)=0$
$x-4-2=0$
$x-6=0$
$x=+6$
So, the oxidation state of sulfur is +6.

- The oxidation state of sulfur in $S{{O}_{3}}$, is calculated as follows by taking the oxidation state of oxygen as -2:
$x+3(-2)=0$
$x-6=0$
$x=+6$
So, the oxidation state of sulfur is +6.
From the above discussion the oxidation state of sulfur is +6 in $S{{O}_{3}}$, $S{{O}_{2}}C{{l}_{2}}$, and ${{H}_{2}}S{{O}_{4}}$ and the oxidation state of sulfur is +4 in $HSO_{3}^{-}$.
So, the correct answer is “Option B”.

Note: If the is no charge on the overall compound then the sum of oxidation state of all the elements will be equal to 0, but if there is a charge on the overall charge on the compound then the sum of the oxidation state of elements will be equal to charge.