Which of the following names of the organic compounds is not correctly written ?

Options

A.
B.
C.
D. `CH_(2)=CH-overset(O)overset("||")C-CH=CH_(2)` -Penta - 1, 4 - dien - 3 - one

Explanation

To determine which of the following names of organic compounds is not correctly written, we will analyze each option step by step.

### Step 1: Analyze the first compound
- The first compound is described as having an aldehyde functional group.
- The correct naming involves identifying the longest carbon chain that includes the aldehyde group.
- The substituents (hydroxy and methoxy groups) must be numbered to give the lowest possible numbers.
- The name provided is "benzaldehyde," which is correct for a compound with a benzene ring and an aldehyde group.

**Hint:** Check if the functional group is correctly identified and if the substituents are numbered properly.

### Step 2: Analyze the second compound
- The second compound is described as "3-methyl cyclohexane" with a carbaldehyde group.
- The numbering should start from the carbon of the aldehyde group to give it the lowest possible number.
- If the aldehyde is at position 1, the correct name should reflect that, such as "1-methylcyclohexanecarbaldehyde."

**Hint:** Ensure that the aldehyde group is given the lowest number in the name.

### Step 3: Analyze the third compound
- The third compound has an aldehyde at position 1 and a chloro substituent at position 2.
- The name is given as "2-H2-2-chlorophenyl ethanol," which seems incorrect.
- The correct naming should reflect the aldehyde and the chloro substituent properly, likely as "2-chloro-2-phenylethanol."

**Hint:** Verify that the functional groups and substituents are correctly represented in the name.

### Step 4: Analyze the fourth compound
- The fourth compound is described as having a symmetrical structure with a diene and an aldehyde.
- The name provided is "pent-1,4-diene," which is correct if the aldehyde is at position 1.
- The diene is correctly named based on the positions of the double bonds.

**Hint:** Check if the diene and aldehyde are correctly named based on their positions.

### Conclusion
After analyzing each compound, it is clear that the second compound's name "3-methyl cyclohexane" with an aldehyde is not correctly written. The correct name should indicate the position of the aldehyde.

### Final Answer
The name of the organic compound that is not correctly written is **B**: "3-methyl cyclohexane with carbaldehyde."

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