How many alkyl groups are possible for iso-octane?

Answer

To determine how many alkyl groups are possible for iso-octane, we need to analyze its structure and identify the different types of carbon atoms present. Here's a step-by-step solution:

### Step 1: Understand the Structure of Iso-Octane
Iso-octane is a branched-chain alkane with the molecular formula C8H18. Its structure can be represented as follows:

```
CH3
|
CH3-CH-CH2-CH-CH3
|
CH3
```

In this structure, we can see that iso-octane has a central carbon atom that is connected to other carbon atoms.

### Step 2: Identify the Types of Carbon Atoms
In iso-octane, we can categorize the carbon atoms based on the number of hydrogen atoms attached to them:

1. **Primary (1°) Carbon**: A carbon atom bonded to one other carbon atom. In iso-octane, the terminal CH3 groups are primary carbons.
2. **Secondary (2°) Carbon**: A carbon atom bonded to two other carbon atoms. The CH2 group in the middle is a secondary carbon.
3. **Tertiary (3°) Carbon**: A carbon atom bonded to three other carbon atoms. The central carbon atom (connected to two other carbons and one CH3) is a tertiary carbon.
4. **Quaternary (4°) Carbon**: A carbon atom bonded to four other carbon atoms. Iso-octane does not have a quaternary carbon.

### Step 3: Count the Different Types of Carbon Atoms
From the structure of iso-octane, we can identify the following types of carbon atoms:
- 3 Primary (1°) Carbons (the three CH3 groups)
- 1 Secondary (2°) Carbon (the CH2 group)
- 1 Tertiary (3°) Carbon (the central carbon)

### Step 4: Conclusion
In total, we have identified 4 different types of carbon atoms in iso-octane. Therefore, the number of alkyl groups possible for iso-octane is **4**.

### Final Answer
**4 alkyl groups are possible for iso-octane.**

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