Which one of the following is the correct match?

Options

A. `Cl_(2)-` only reducing agent
B. `HNO_(2)-` only oxidising agent
C. `HNO_(3)-` both oxidising and reducing agent
D. `SO_(2)-` both oxidising and reducing agent

Answer

To determine the oxidation number of the oxygen atom in the O3 molecule (ozone), we can follow these steps:

### Step 1: Understand the elemental form
Ozone (O3) is a molecule made up of three oxygen atoms. Since it is composed of the same element, it is considered to be in its elemental form.

### Step 2: Assign oxidation states in elemental form
In chemistry, the oxidation state of an element in its elemental form is always 0. This applies to all diatomic and polyatomic molecules made up of the same element, such as O2 (oxygen gas), N2 (nitrogen gas), and P4 (white phosphorus).

### Step 3: Apply the rule to O3
Since ozone is composed entirely of oxygen atoms, we assign the oxidation state of each oxygen atom in O3 as follows:
- The oxidation state of each oxygen atom in O3 = 0

### Step 4: Conclusion
Thus, the oxidation number of each oxygen atom in the O3 molecule is 0.

### Final Answer
The oxidation number of oxygen in O3 is 0.

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