Which of the following statements are wrong?

Options

A. `m`-Chlorobromo benzene is an isomer of `m`-bromochloro benzene.
B. All alkenes show geometrical isomerism.
C. Dimethyl ether and ethanol are functional isomers.
D. Geometrical isomers have different physical properties.

Explanation

To determine which statements are wrong, we need to analyze each option provided in the question.

### Step-by-Step Solution:

1. **Analyze the First Statement:**
- The first statement claims that metachlorobromobenzene is an isomer of metachlorobromochlorobenzene.
- To check this, we need to draw both compounds:
- **Metachlorobromobenzene**: This compound has a chlorine atom and a bromine atom on the benzene ring at the meta positions.
- **Metachlorobromochlorobenzene**: This compound has two chlorine atoms and one bromine atom on the benzene ring.
- Since both compounds have the same molecular formula and the same connectivity of atoms, they are not isomers. Therefore, the first statement is **wrong**.

2. **Analyze the Second Statement:**
- The second statement claims that all alkenes show symmetrical isomerism.
- This is incorrect because alkenes can exhibit geometrical isomerism (cis-trans isomerism) only when there are different groups attached to the double bond. For example, if we have an alkene with two identical groups, it cannot exhibit geometrical isomerism.
- Therefore, the second statement is also **wrong**.

3. **Analyze the Third Statement:**
- The third statement claims that dimethyl ether and ethanol are functional isomers.
- Dimethyl ether (CH3OCH3) and ethanol (C2H5OH) have the same molecular formula (C2H6O) but different functional groups (ether vs. alcohol).
- Since they have different functional groups, this statement is **correct**.

4. **Analyze the Fourth Statement:**
- The fourth statement claims that geometrical isomers have different physical properties.
- Geometrical isomers (cis and trans forms) indeed have different physical properties such as boiling points and melting points due to their different spatial arrangements.
- Therefore, this statement is also **correct**.

### Conclusion:
- The wrong statements are:
- **First Statement**: Metachlorobromobenzene is not an isomer of metachlorobromochlorobenzene.
- **Second Statement**: Not all alkenes show symmetrical isomerism.