IUPAC Name of some compounds are given . Which one is incorrect -

Options

A. `{:(" "CH_(3)),(" "|),(CH_(3)-CH_(2)-CH_(2)-CH-CH-CH_(2)CH_(3)),(" "|),(" "CH_(2)CH_(3)),("3-Methyl-4-ethyl-heptance"):}`
B. `{:(CH_(3)-CH-CH-CH_(3)),(" | |"),(" "OH" " CH_(3)),("3-Methyl-2-butanol"):}`
C. `{:(CH_(3)-CH_(2)-C" "-" "CH-CH_(3)),(" || "|),(" "CH_(2)" "CH_(3)),(" 2-Ethyl-3-methyl-but-1-ene"):}`
D. `{:(CH_(3)-C-=C-CH(CH_(3))_(2)),("4-Methyl-2-pentyne"):}`

Answer

To determine which IUPAC name among the given options is incorrect, we need to follow the systematic rules of naming organic compounds. Here’s a step-by-step solution:

### Step 1: Identify the Longest Continuous Chain
- Look for the longest continuous carbon chain in the compound. This will be the base name of the compound.

### Step 2: Identify the Substituents
- Identify any substituent groups attached to the longest chain. These could be alkyl groups (like methyl, ethyl, etc.) or functional groups (like hydroxyl, carbonyl, etc.).

### Step 3: Number the Chain
- Number the carbon chain starting from the end nearest to the first substituent. This ensures that the substituents get the lowest possible numbers.

### Step 4: Designate the Location of Substituents
- Assign numbers to the substituents based on their position on the carbon chain.

### Step 5: Write the Name
- Combine the names of the substituents and the base name of the compound. When listing substituents, they should be arranged in alphabetical order regardless of their position numbers.

### Example Analysis
Let’s analyze the provided options based on the above steps:

1. **Option A**:
- Longest chain: 7 carbons (heptane).
- Substituents: 3-methyl and 4-ethyl.
- Correct name: 4-ethyl-3-methylheptane (substituents in alphabetical order).
- **Conclusion**: This name is incorrect as it should be 4-ethyl-3-methylheptane.

2. **Option B**:
- Longest chain: 4 carbons (butane).
- Substituent: 3-methyl.
- Correct name: 3-methylbutanol.
- **Conclusion**: This name is correct.

3. **Option C**:
- Longest chain: 4 carbons (butane).
- Substituents: 2-ethyl and 3-methyl.
- Correct name: 2-ethyl-3-methylbutane.
- **Conclusion**: This name is correct.

4. **Option D**:
- Longest chain: 5 carbons (pentane).
- Substituent: 4-methyl.
- Functional group: triple bond (alkyne).
- Correct name: 4-methyl-1-pentyne.
- **Conclusion**: This name is correct.

### Final Conclusion
The incorrect IUPAC name among the options provided is **Option A**: 4-ethyl-3-methylheptane.