The IUPAC name of `CH_3-overset(O)overset(||)C- underset(C_2 H_5) underset(|) CH -underset(CH_3)underset(|)CH-CH_3 ` is

Options

A. 3-(Methylethyl) pentan-2-one
B. 3-(Methylethyl)pentan-4-one
C. 3-Ethyl-4-methylpentan-2-one
D. 3-Ethyl-2-methylpentan-4-one

Explanation

To determine the IUPAC name of the compound `CH3-CO-CH(C2H5)-CH(CH3)-CH3`, we will follow these steps:

### Step 1: Identify the Structure
The compound can be represented as:
- A carbon chain with a ketone functional group (C=O).
- The structure includes:
- A methyl group (CH3) attached to the fourth carbon.
- An ethyl group (C2H5) attached to the third carbon.

### Step 2: Determine the Longest Carbon Chain
We need to find the longest continuous carbon chain that includes the ketone functional group. The longest chain here consists of 5 carbon atoms:
1. CH3 (1)
2. CO (2)
3. CH (3)
4. CH (4)
5. CH3 (5)

### Step 3: Number the Carbon Chain
We will number the carbon chain starting from the end closest to the functional group (the ketone). This ensures that the ketone gets the lowest possible number:
- 1: CH3
- 2: CO (ketone)
- 3: CH (with ethyl group)
- 4: CH (with methyl group)
- 5: CH3

### Step 4: Identify the Substituents
From the numbering:
- At carbon 3, there is an ethyl group (C2H5).
- At carbon 4, there is a methyl group (CH3).

### Step 5: Write the IUPAC Name
According to IUPAC nomenclature:
1. List the substituents in alphabetical order, along with their positions.
2. The parent chain is pentane (5 carbons).
3. The ketone functional group is at position 2, so we use "pentan-2-one".

Putting it all together:
- Ethyl is at position 3.
- Methyl is at position 4.
- The correct name is: **3-ethyl-4-methylpentan-2-one**.

### Final Answer
The IUPAC name of the compound is **3-ethyl-4-methylpentan-2-one**.

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