Problem 23 - Chemistry The Central Science

Question

Do the reactions involved in ozone depletion involve changes in oxidation state of the O atoms? Explain.

Step-by-Step Solution

Answer

In the reactions involved in ozone depletion, the oxidation state of the O atoms does not change. In the formation of ozone from molecular oxygen and the destruction of ozone by chlorine radicals, the oxidation state of O atoms remains the same throughout the reactions.

Step 1: Identify the main reactions involved in ozone depletion

The main reactions involved in ozone depletion are: 1. Formation of ozone (O3) from molecular oxygen (O2) by ultraviolet (UV) radiation: \[ O_2 + UV \rightarrow 2 O \] \[ O + O_2 \rightarrow O_3 \] 2. Destruction of ozone (O3) by chlorine (Cl) radicals: \[ Cl + O_3 \rightarrow ClO + O_2 \] \[ ClO + O \rightarrow Cl + O_2 \]

Step 2: Determine the oxidation state of O atoms in each reaction

To determine the oxidation state change, we first identify the oxidation state of each element in the reactants and products: 1. Formation of ozone (O3) from molecular oxygen (O2) by ultraviolet (UV) radiation: - O2: Each O atom has an oxidation state of 0, as it's in its elemental form. - O3: Each O atom has an average oxidation state of 0, as they are in different oxidation states but have equal contributions (one O atom is +2, and two O atoms are -1). 2. Destruction of ozone (O3) by chlorine (Cl) radicals: - Cl: The oxidation state is 0, as it's in its elemental form. - ClO: The Cl atom has an oxidation state of +1, and the O atom has an oxidation state of -1.

Step 3: Determine if there's a change in the oxidation state of O atoms

1. Formation of ozone (O3) from molecular oxygen (O2) by ultraviolet (UV) radiation: - In this reaction, the oxidation state of O atoms remains 0 in both O2 and O3. Therefore, there is no change in the oxidation state of the O atoms in this reaction. 2. Destruction of ozone (O3) by chlorine (Cl) radicals: - In the reaction between Cl and O3, there's no change in the oxidation state of the O atoms (-1 in ClO and O3). - In the reaction between ClO and O, again, there's no change in the oxidation state of the O atoms (-1 in ClO and O).

Step 4: Conclusion

In conclusion, the reactions involved in ozone depletion do not involve changes in the oxidation state of the O atoms. Both in the formation of ozone from molecular oxygen and in the destruction of ozone by chlorine radicals, the oxidation state of the O atoms remains the same.