The correct IUPAC name of the compound
`CH_(3)-overset(H_(3)C)overset(|)C= overset(H)overset(|)C-COOH` is

Options

A. 2-methylbut-2-enoic acid
B. 3-methylbut-3-enoic acid
C. 3-methylbut-2-enoic acid
D. 2-methylbut-3-enoic acid

Explanation

To find the correct IUPAC name of the compound `CH3-CH(CH3)-C=CH-COOH`, we will follow these steps:

### Step 1: Identify the Longest Carbon Chain
First, we need to identify the longest continuous carbon chain in the compound. In this case, the longest chain consists of 4 carbon atoms.

### Step 2: Number the Carbon Chain
Next, we will number the carbon chain. We will start numbering from the end closest to the functional group (COOH) to give it the lowest locant.

- If we number from the left (1 to 4):
1. CH3 (C1)
2. CH (C2)
3. C=C (C3)
4. COOH (C4)

- If we number from the right:
1. COOH (C1)
2. C=C (C2)
3. CH (C3)
4. CH3 (C4)

Since we want the functional group (carboxylic acid) to have the lowest number, we will number from the right.

### Step 3: Identify Substituents
Now, we will identify the substituents on the main carbon chain. There is a methyl group (CH3) attached to the second carbon (C2).

### Step 4: Identify the Functional Group
The functional group present in this compound is the carboxylic acid (COOH). The suffix for carboxylic acids is "-oic acid".

### Step 5: Determine the Alkene Suffix
Since there is a double bond between C2 and C3, we will use the suffix "-ene". The double bond is located between the second and third carbon, so we will indicate this with the locant "2".

### Step 6: Combine All Parts for the IUPAC Name
Now we can combine all the parts to form the complete IUPAC name. The parent chain has 4 carbons (butane), and since there is a double bond starting at C2, we will write "but-2-ene". After that, we will add the carboxylic acid suffix, which gives us "but-2-enoic acid".

### Final IUPAC Name
Thus, the correct IUPAC name of the compound is **4-methylbut-2-enoic acid**.

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