Which of the following given moleculues in a pair are paramagnetic and ferrimagnetic substance respectively?

Options

A. `Fe_3 O_4' & 'H_2 O`
B. `MnO & 'CrO_2`
C. `Cu^2+` & `ZnFe_2 O_4`
D. `C_6 H_6' & 'O_2`

Answer

To determine which of the given molecules in a pair are paramagnetic and ferrimagnetic substances, we need to understand the definitions and characteristics of both types of magnetism.

### Step-by-Step Solution:

1. **Define Paramagnetism:**
- Paramagnetic substances are those that have unpaired electrons in their atomic or molecular orbitals. The presence of unpaired electrons leads to a net magnetic moment, allowing these substances to be attracted by an external magnetic field.

2. **Identify Examples of Paramagnetic Substances:**
- Common examples of paramagnetic substances include:
- Oxygen (O2)
- Copper (Cu^2+)
- Iron (Fe^3+)
- Chromium (Cr^3+)

3. **Define Ferrimagnetism:**
- Ferrimagnetic substances have magnetic moments that align in both parallel and anti-parallel directions, but in unequal numbers. This results in a net magnetic moment, which is characteristic of ferrimagnetic materials.

4. **Identify Examples of Ferrimagnetic Substances:**
- Common examples of ferrimagnetic substances include:
- Magnetite (Fe3O4)
- Ferrites such as MgFe2O4 and ZnFe2O4.

5. **Analyze the Given Pairs:**
- For each pair of molecules provided in the question, we need to check for the presence of unpaired electrons to identify paramagnetic substances and check for the characteristics of ferrimagnetism for ferrimagnetic substances.

6. **Determine the Correct Pair:**
- After analyzing the options, we find that one option contains a paramagnetic substance (like Cu^2+) and a ferrimagnetic substance (like Fe3O4).

7. **Conclusion:**
- The correct answer will be the pair where one molecule is identified as paramagnetic and the other as ferrimagnetic.