Among the following, the paramagnetic species is:

Options

A. Free radical
B. Carbocation
C. Carbanion
D. All the three

Answer

To determine which of the given species is paramagnetic, we need to analyze each option based on the presence of unpaired electrons. A species is considered paramagnetic if it has one or more unpaired electrons in its molecular or atomic orbitals.

### Step-by-Step Solution:

1. **Identify the Species**: The options given are:
- Free radical
- Carbocation
- Carbon anion
- All three

2. **Analyze the Free Radical**:
- A free radical has an unpaired electron. For example, consider the methyl radical (CH3•), which has one unpaired electron.
- Since it has an unpaired electron, the free radical is **paramagnetic**.

3. **Analyze the Carbocation**:
- A carbocation, such as CH3+, has all its electrons paired in the bonding orbitals. The positive charge indicates that one electron is missing, but it does not create an unpaired electron.
- Therefore, a carbocation is **not paramagnetic**.

4. **Analyze the Carbon Anion**:
- A carbon anion, like CH3-, has an extra electron, which means that all electrons are paired. The negative charge results from an added electron, but it does not lead to unpaired electrons.
- Hence, a carbon anion is **not paramagnetic**.

5. **Conclusion**:
- Among the options, only the free radical has unpaired electrons, making it the only **paramagnetic species**.

### Final Answer:
The paramagnetic species among the given options is the **free radical**.