How mahy types of carbon atoms are present in 2,2,3-trimethylpentane

Options

A. One
B. Two
C. Three
D. Four

Answer

To determine how many types of carbon atoms are present in 2,2,3-trimethylpentane, we can follow these steps:

### Step 1: Identify the structure of 2,2,3-trimethylpentane
2,2,3-trimethylpentane is a branched alkane. The name indicates that the parent chain is pentane (which has 5 carbon atoms), and there are three methyl (−CH₃) groups attached to the second and third carbon atoms of the chain.

### Step 2: Draw the structure
The structure can be drawn as follows:
- Start with a straight chain of 5 carbon atoms (the pentane backbone).
- Add two methyl groups (−CH₃) to the second carbon.
- Add one methyl group (−CH₃) to the third carbon.

The structure looks like this:
```
CH3
|
CH3 - C - C - CH2 - CH3
|
CH3
```

### Step 3: Identify the types of carbon atoms
Now, we will classify the carbon atoms based on their connectivity:
- **Primary carbon (1°)**: A carbon atom bonded to only one other carbon atom. In this structure, the terminal carbon atoms (the ones at the ends of the chain) are primary.
- **Secondary carbon (2°)**: A carbon atom bonded to two other carbon atoms. The second carbon in the chain (the one with two methyl groups) is a secondary carbon.
- **Tertiary carbon (3°)**: A carbon atom bonded to three other carbon atoms. The third carbon in the chain (the one with one methyl group and two other carbons) is a tertiary carbon.
- **Quaternary carbon (4°)**: A carbon atom bonded to four other carbon atoms. In this case, the second carbon is also a quaternary carbon because it is connected to three methyl groups and one carbon from the chain.

### Step 4: Count the types of carbon atoms
1. **Primary Carbons**: 2 (the two terminal carbons)
2. **Secondary Carbons**: 1 (the second carbon)
3. **Tertiary Carbons**: 1 (the third carbon)
4. **Quaternary Carbons**: 1 (the second carbon again, as it is connected to four other carbons)

### Conclusion
In total, we have:
- 2 Primary Carbons
- 1 Secondary Carbon
- 1 Tertiary Carbon
- 1 Quaternary Carbon

Thus, there are **4 types of carbon atoms** present in 2,2,3-trimethylpentane.

### Final Answer
The correct answer is 4 types of carbon atoms.

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