Spin isomerism is shown by

Options

A. Dichloro benzene
B. Hydrogen
C. Dibasic acid
D. n-butane

Answer

To solve the question "Spin isomerism is shown by," we need to understand the concept of spin isomerism and identify the relevant substance that exhibits this property.

### Step-by-Step Solution:

1. **Understanding Spin Isomerism**:
- Spin isomerism is a type of isomerism that occurs due to the different alignments of nuclear spins of protons in a molecule.
- Isomers formed by changing the alignment of proton nuclear spins are called spin isomers.

2. **Identifying the Substance**:
- The question asks which substance shows spin isomerism. The most common example of a substance that exhibits spin isomerism is hydrogen (specifically dihydrogen, H₂).
- Dihydrogen (H₂) consists of two hydrogen atoms, each with one proton.

3. **Characteristics of Hydrogen**:
- Hydrogen has an atomic number of 1, which is odd.
- In dihydrogen (H₂), the two protons can align in two different ways:
- **Ortho-hydrogen**: Both protons have their spins aligned in the same direction (parallel).
- **Para-hydrogen**: The spins of the protons are aligned in opposite directions (antiparallel).

4. **Conclusion**:
- Since dihydrogen (H₂) can exist in two different spin states (ortho and para), it clearly demonstrates spin isomerism.
- Therefore, the answer to the question is that spin isomerism is shown by hydrogen (H₂).

### Final Answer:
Spin isomerism is shown by hydrogen (H₂).

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