In H₂SO₃ (sulfurous acid), the oxidation state of sulfur (S) is +4. This can be determined by considering the oxidation states of hydrogen (H) and oxygen (O) in the compound. Hydrogen is generally assigned an oxidation state of +1 in compounds, and oxygen is typically assigned an oxidation state of -2. Since the compound is neutral, the sum of the oxidation states must be zero. Therefore, we can calculate the oxidation state of sulfur as follows: 2(oxidation state of H) + oxidation state of S + 3(oxidation state of O) = 0 2(+1) + oxidation state of S + 3(-2) = 0 2 + oxidation state of S - 6 = 0 oxidation state of S - 4 = 0 oxidation state of S = +4 In H₂SO₈ (sulfuric acid), the oxidation state of sulfur (S) is +6. Following a similar reasoning as before, we can assign the oxidation states: 2(oxidation state of H) + oxidation state of S + 4(oxidation state of O) = 0 2(+1) + oxidation state of S + 4(-2) = 0 2 + oxidation state of S - 8 = 0 oxidation state of S - 6 = 0 oxidation state of S = +6 Therefore, the oxidation state of sulfur in H₂SO₃ (sulfurous acid) is +4, and the oxidation state of sulfur in H₂SO₈ (sulfuric acid) is +6.
Redox reactions are chemical reactions where oxidation and reduction take place simultaneously. In this type of reaction, there is a gain of electrons for one chemical species while the other loses electrons or simply involves transfer of electrons. The species that loses electrons is oxidized while the one that gains electrons is reduced.
Types of Redox Reactions:
Redox reactions can be differentiated into 4 categories namely combination reactions, decomposition reactions, displacement reactions, and disproportionation reactions. Each is explained separately below:
Combination Reaction:
In this, the molecules combine to form new compounds. For example, when magnesium reacts to nitrogen.
Decomposition Reaction:
Opposite to the combination reaction, here there is a breakdown of compounds to simpler substances. For example, electrolysis of water.
Displacement Reaction:
In this, the more reactive metal will displace the less reactive one in a chemical reaction. The reactivity of an element is represented in a series called the reactivity series (arranged in decreasing order of reactivity) which makes it easier to determine the chemical reaction and its products.
Disproportionation Reaction:
This is a peculiar type of reaction where an element showing a particular oxidation state will be oxidized and reduced simultaneously. Another thing to note is that these reactions will always have an element that can exhibit three oxidation states.
