Which of the following oxide is basic ?

Options

A. `CrO`
B. `Cr_(2)O_(3)`
C. `CrO_(3)`
D. `Cr_(2)O_(4)`

Answer

To determine which of the given oxides is basic, we will analyze the oxidation states of chromium in each oxide and their corresponding acidic or basic nature.

### Step-by-Step Solution:

1. **Identify the Oxides**: The oxides given are:
- CrO
- Cr2O3
- CrO3
- Cr2O4

2. **Determine the Oxidation State of Chromium in Each Oxide**:
- **For CrO**:
- Let the oxidation state of Cr be \( X \).
- The equation is: \( X + (-2) = 0 \) (since oxygen has a charge of -2).
- Solving gives: \( X = +2 \).
- **For Cr2O3**:
- Let the oxidation state of Cr be \( X \).
- The equation is: \( 2X + 3(-2) = 0 \).
- Solving gives: \( 2X - 6 = 0 \) or \( 2X = 6 \) leading to \( X = +3 \).
- **For CrO3**:
- Let the oxidation state of Cr be \( X \).
- The equation is: \( X + 3(-2) = 0 \).
- Solving gives: \( X - 6 = 0 \) or \( X = +6 \).
- **For Cr2O4**:
- Let the oxidation state of Cr be \( X \).
- The equation is: \( 2X + 4(-2) = 0 \).
- Solving gives: \( 2X - 8 = 0 \) or \( 2X = 8 \) leading to \( X = +4 \).

3. **Analyze the Basicity/Acidity of Each Oxide**:
- **CrO**: Chromium is in the +2 oxidation state. Lower oxidation states typically indicate basic character.
- **Cr2O3**: Chromium is in the +3 oxidation state. This oxide is amphoteric, meaning it can act as both an acid and a base.
- **CrO3**: Chromium is in the +6 oxidation state. Higher oxidation states indicate acidic character.
- **Cr2O4**: Chromium is in the +4 oxidation state. This oxide is also amphoteric.

4. **Conclusion**: Among the given oxides, CrO is the only oxide that is basic in nature.

### Final Answer:
The basic oxide among the given options is **CrO**.

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