In which compound oxygen does not show - 2 oxidation state:

Options

A. `H_2O`
B. `CO_2`
C. `F_2O`
D. `OCl_2`

Explanation

To determine in which compound oxygen does not show a -2 oxidation state, we will analyze the oxidation states of oxygen in the given compounds step by step.

### Step 1: Identify the compounds
We are given four compounds to analyze for the oxidation state of oxygen:
1. H₂O
2. CO₂
3. F₂O
4. Cl₂O

### Step 2: Analyze H₂O
In water (H₂O):
- Hydrogen (H) has an oxidation state of +1.
- There are two hydrogen atoms, contributing a total of +2.
- To balance this, oxygen must have an oxidation state of -2.

Thus, in H₂O, oxygen shows a -2 oxidation state.

**Hint:** Remember that hydrogen typically has a +1 oxidation state.

### Step 3: Analyze CO₂
In carbon dioxide (CO₂):
- Carbon (C) has an oxidation state of +4.
- There are two oxygen atoms, which must balance the +4 from carbon.
- Therefore, the total oxidation state of the two oxygen atoms must be -4, which means each oxygen has an oxidation state of -2.

Thus, in CO₂, oxygen also shows a -2 oxidation state.

**Hint:** The sum of oxidation states in a neutral compound must equal zero.

### Step 4: Analyze F₂O
In fluorine oxide (F₂O):
- Fluorine (F) is more electronegative than oxygen and has an oxidation state of -1.
- There are two fluorine atoms, contributing a total of -2.
- To balance this, oxygen must have an oxidation state of +2.

Thus, in F₂O, oxygen shows a +2 oxidation state, which is an exception to the usual -2 state.

**Hint:** The most electronegative element will dictate the oxidation state of less electronegative elements in compounds.

### Step 5: Analyze Cl₂O
In dichlorine monoxide (Cl₂O):
- Chlorine (Cl) has an oxidation state of +1.
- There are two chlorine atoms, contributing a total of +2.
- To balance this, oxygen must have an oxidation state of -2.

Thus, in Cl₂O, oxygen shows a -2 oxidation state.

**Hint:** Check the electronegativity of the elements involved to determine oxidation states.

### Conclusion
From our analysis, the compound in which oxygen does not show a -2 oxidation state is **F₂O**, where oxygen has a +2 oxidation state.

**Final Answer:** F₂O