Identify the correct statement

Options

A. Lead forms compounds in +2 oxidation state due to inert pair effect
B. All halogens form only negative oxidation states
C. Catenation property increases from boron to oxygen
D. Oxygen's oxidation state is - 1 in ozonides

Answer

To solve the question of identifying the correct statement among the given options, we will analyze each statement step by step.

### Step-by-Step Solution:

1. **Analyzing the First Statement**:
- The first statement claims that lead forms compounds in the +2 oxidation state due to the inert pair effect.
- Lead (Pb) has an atomic number of 82 and belongs to the carbon family (Group 14).
- Its electronic configuration is [Xe] 6s² 6p².
- The inert pair effect refers to the tendency of the s-electrons (in this case, the 6s² electrons) to remain unshared in compounds, leading to a more stable +2 oxidation state compared to +4.
- Therefore, this statement is **true**.

2. **Analyzing the Second Statement**:
- The second statement asserts that all halogens form only negative oxidation states.
- While halogens typically have a -1 oxidation state, they can also exhibit positive oxidation states.
- For example, bromine (Br) can have a +3 oxidation state in compounds like BrF₃.
- Hence, this statement is **false**.

3. **Analyzing the Third Statement**:
- The third statement suggests that catenation property increases from boron to oxygen.
- Catenation is the ability of an element to form chains of atoms through covalent bonds.
- Carbon exhibits the highest catenation ability, while oxygen has a much lower catenation property.
- Thus, this statement is **false**.

4. **Analyzing the Fourth Statement**:
- The fourth statement claims that the oxidation state of oxygen in ozonide (O₃⁻) is -1.
- In ozonide, the total charge is -1, and since there are three oxygen atoms, the average oxidation state of each oxygen atom is -1/3.
- Therefore, this statement is **false**.

### Conclusion:
After analyzing all statements, the only correct statement is the first one regarding lead and the inert pair effect.

Thus, the correct answer is:
**Option A: Lead forms compounds in +2 oxidation state due to inert pair effect.**