(a) SO2 (b) H2S (c) SO4 (d) S8 (e) SCl2 (f) SF6 (g) Fe2(SO3)3 (h) HSO4 (i) (NH4)2SO4
The Correct Answer and Explanation is:
To determine the oxidation state of sulfur in each of these compounds, we need to follow the rules for oxidation states:
- The oxidation state of an atom in a free element is 0.
- In compounds, the oxidation state of hydrogen is usually +1, and the oxidation state of oxygen is usually -2.
- The sum of oxidation states in a neutral compound is zero, and the sum in a polyatomic ion is equal to the charge of the ion.
Let’s apply these rules to each compound:
(a) SO2 (Sulfur Dioxide):
In SO2, oxygen is assigned an oxidation state of -2. Since there are two oxygens, the total contribution from oxygen is -4. The compound is neutral, so the oxidation state of sulfur must balance this, giving sulfur an oxidation state of +4.
(b) H2S (Hydrogen Sulfide):
In H2S, hydrogen has an oxidation state of +1. Since there are two hydrogens, the total contribution from hydrogen is +2. The compound is neutral, so the oxidation state of sulfur must balance this, giving sulfur an oxidation state of -2.
(c) SO4^2- (Sulfate Ion):
In the sulfate ion (SO4^2-), oxygen is assigned an oxidation state of -2. Since there are four oxygens, the total contribution from oxygen is -8. The ion has a -2 charge, so the oxidation state of sulfur must be +6 to balance this charge.
(d) S8 (Sulfur Molecule):
In S8, sulfur is in its elemental form, so the oxidation state of sulfur is 0.
(e) SCl2 (Sulfur Dichloride):
In SCl2, chlorine has an oxidation state of -1. Since there are two chlorines, the total contribution from chlorine is -2. The compound is neutral, so the oxidation state of sulfur must be +2 to balance this.
(f) SF6 (Sulfur Hexafluoride):
In SF6, fluorine has an oxidation state of -1. Since there are six fluorines, the total contribution from fluorine is -6. The compound is neutral, so the oxidation state of sulfur must be +6 to balance this.
(g) Fe2(SO3)3 (Iron(III) Sulfite):
In Fe2(SO3)3, each sulfite ion (SO3^2-) has a charge of -2. The total charge of the sulfite ions is -6. The two iron ions must balance this charge, so each iron has an oxidation state of +3. In each sulfite ion, sulfur must have an oxidation state of +4 (since oxygen contributes -6, and the total charge is -2).
(h) HSO4^- (Hydrogen Sulfate Ion):
In HSO4^-, hydrogen has an oxidation state of +1, and oxygen has an oxidation state of -2. Since there are four oxygens, the total contribution from oxygen is -8. The ion has a -1 charge, so the oxidation state of sulfur must be +6 to balance the charge.
(i) (NH4)2SO4 (Ammonium Sulfate):
In (NH4)2SO4, the ammonium ion (NH4+) has a charge of +1, so two ammonium ions contribute a total of +2. The sulfate ion (SO4^2-) has a charge of -2. Therefore, the oxidation state of sulfur in the sulfate ion is +6.
Summary of Oxidation States:
- SO2: +4
- H2S: -2
- SO4^2-: +6
- S8: 0
- SCl2: +2
- SF6: +6
- Fe2(SO3)3: +4
- HSO4-: +6
- (NH4)2SO4: +6
