Which is the correct IUPAC name for `CH_(3)-underset(C_(2)H_(5))underset(|)"CH"-CH_(2)-Br`?

Options

A. 1-bromo-2-ethylpropane
B. 1-bromo-2-ethyl-2-methylethane
C. 1-bromo-2-methylbutane
D. 2-methyl-1-bromobutane

Explanation

To determine the correct IUPAC name for the compound `CH₃-CH(C₂H₅)-CH₂-Br`, we will follow these steps:

### Step 1: Identify the Structure
The given compound can be represented as follows:
- The main chain consists of 4 carbon atoms.
- There is a bromine atom (Br) attached to one of the carbon atoms.
- There is also an ethyl group (C₂H₅) attached to the second carbon of the main chain.

### Step 2: Draw the Structure
Let's draw the structure based on the given formula:
1. Start with the longest carbon chain, which has 4 carbon atoms.
2. The first carbon (C1) will have a bromine atom attached.
3. The second carbon (C2) will have an ethyl group (C₂H₅) attached.
4. The remaining carbon atoms will complete the chain.

The structure looks like this:
```
CH3
|
CH3-CH-CH2-Br
|
CH2-CH3
```

### Step 3: Number the Carbon Chain
Number the carbon chain starting from the end closest to the bromine atom to give the substituents the lowest possible numbers:
1. C1: Br
2. C2: Ethyl group (C₂H₅)
3. C3: Methyl group (C₁H₃)
4. C4: CH₃

### Step 4: Identify Substituents
- The substituents are:
- Bromine (Br) at position 1
- Ethyl group (C₂H₅) at position 2
- Methyl group (C₁H₃) at position 2

### Step 5: Write the IUPAC Name
Combine the substituents with the main chain name:
- The main chain is a butane (4 carbon atoms).
- The substituents are named in alphabetical order. The ethyl group comes before the methyl group.
- Therefore, the name will be: 2-Ethyl-2-methylbutane.

### Final Answer
The correct IUPAC name for the compound `CH₃-CH(C₂H₅)-CH₂-Br` is **1-Bromo-2-ethylbutane**.