Question

In which of the following species does sulfur have the lowest oxidation number? A) S8 B) SO(3)2- C)SO(4)2- D)S(2)O(3)2- E)S2-

Answer 1

$S^{2-}$ is having lowest oxidation number of sulphur in teh options given. The oxidation number is -2.

The correct option is E.

Explanation:

$S^{2-}$ have oxidation number of -2, which is lowest in all the options given.

In the given examples $S_{8}$ will have oxidation number zero because it is in elemental form. In the rules for oxidation number it is given that any element in free state has its oxidation number zero.

All other options are in compound form as:

S$O_{3} ^{2-}$ =  oxidation number is +4. It is calculated as oxygen having O.N of -2,

The charge on the atom is -2, so sum of the oxidation numbers of all the elements should be equal to -2.

x+3(-2)= -2

x = 4

S$O_{4} ^{2-}$= The charge on the atom is -2, so sum of the oxidation numbers of all the elements should be equal to -2.

x +4(-2) = -2

x = +6

$S_{2}O_{3^{2-} }$

The charge on the atom is -2, so sum of the oxidation numbers of all the elements should be equal to -2.

2x + 3(-2) = -2

2x = 4

x = 2

$S^{2-}$= oxidation number is -2 as the charge on ion in equal to its oxidation number.