In the disproportionation reaction CI2 + H2Omc021-1.jpgHCIO + HCI, what describes the oxidation states of the substance Cl?
Cl has an oxidation number of 2 in Cl2. It is then reduced to Cl with an oxidation number of 1 in both HCl and HClO.
Cl has an oxidation number of –1 in Cl2. It is then oxidized to Cl with an oxidation number of 1 in both HCl and HClO.
Cl has an oxidation number of 0 in Cl2. It is then reduced to CI- with an oxidation number of –1 in both HCl and HClO.
Cl has an oxidation number of 0 in Cl2. It is then reduced to CI- with an oxidation number of –1 in HCl and is oxidized to Cl+ with an oxidation number +1 in HClO.
The Correct Answer and Explanation is :
The correct answer is:
Cl has an oxidation number of 0 in Cl2. It is then reduced to Cl– with an oxidation number of –1 in HCl and is oxidized to Cl+ with an oxidation number of +1 in HClO.
Explanation:
In the disproportionation reaction:
[ \text{Cl}_2 + \text{H}_2\text{O} \rightarrow \text{HCl} + \text{HClO} ]
The chlorine (Cl) undergoes both oxidation and reduction, which is why it’s called a disproportionation reaction. Let’s break down the oxidation states of chlorine in the reaction:
- Chlorine in Cl2:
Chlorine (Cl2) is a molecule of two chlorine atoms. In elemental chlorine, the oxidation state of each chlorine atom is 0. This is because Cl2 is in its most basic, unoxidized state. - Chlorine in HCl:
In hydrochloric acid (HCl), chlorine forms an ionic bond with hydrogen. The oxidation state of chlorine in HCl is -1 because the hydrogen atom has an oxidation state of +1, and chlorine must balance it to achieve a neutral molecule. - Chlorine in HClO:
In hypochlorous acid (HClO), chlorine is bonded to hydrogen and oxygen. The oxidation state of chlorine here is +1. Oxygen typically has an oxidation state of -2, and hydrogen is +1. For the molecule to be neutral, chlorine must have an oxidation state of +1 to balance the -2 from oxygen and +1 from hydrogen.
Redox Process (Oxidation and Reduction):
- In Cl2, chlorine starts with an oxidation state of 0.
- One chlorine atom is reduced to -1 in HCl (gains an electron).
- The other chlorine atom is oxidized to +1 in HClO (loses an electron).
Thus, chlorine undergoes disproportionation, where one atom is reduced and the other is oxidized. This reaction demonstrates a classic case of disproportionation where a single substance (Cl2) reacts to form products with two different oxidation states of the same element.