nitromethane will exhibit which type of isomerism?

Options

A. metamerism
B. geometrical isomerism
C. tautomerism
D. optical isomerism

Answer

To determine the type of isomerism exhibited by nitromethane, we will analyze its structure and evaluate the different types of isomerism.

### Step-by-Step Solution:

1. **Identify the Structure of Nitromethane**:
- The molecular formula of nitromethane is \( CH_3NO_2 \).
- The structure consists of one carbon atom (C) bonded to three hydrogen atoms (H) and one nitro group (NO2).

2. **Evaluate Metamerism**:
- Metamerism occurs when compounds have the same molecular formula but different structural arrangements due to the shifting of carbon atoms.
- Since nitromethane has only one carbon atom, it cannot exhibit metamerism.

3. **Evaluate Geometrical Isomerism**:
- Geometrical isomerism (cis-trans isomerism) occurs in compounds with restricted rotation around a double bond and requires at least two carbon atoms.
- Nitromethane does not have a double bond between carbon atoms, so it cannot exhibit geometrical isomerism.

4. **Evaluate Tautomerism**:
- Tautomerism involves isomers that can readily interconvert, typically involving the relocation of a hydrogen atom and a shift in bonding.
- Nitromethane has an alpha hydrogen (the hydrogen attached to the carbon adjacent to the functional group), which allows it to exhibit tautomerism.

5. **Evaluate Optical Isomerism**:
- Optical isomerism occurs in compounds that are chiral, meaning they have non-superimposable mirror images.
- Nitromethane does not have a chiral center (it has a symmetrical structure), so it cannot exhibit optical isomerism.

### Conclusion:
Based on the analysis, nitromethane primarily exhibits **tautomerism**.

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