What is the molecular formula for the alkane of smallest molecular weight which possesses a stereogenic centre?

Options

A. `C_(7)H_(16)`
B. `C_(6)H_(14)`
C. `C_(5)H_(12)`
D. `C_(8)H_(18)`

Explanation

To determine the molecular formula for the alkane with the smallest molecular weight that possesses a stereogenic center, we can follow these steps:

### Step 1: Understand the concept of a stereogenic center
A stereogenic center (or chiral center) is a carbon atom that is bonded to four different groups. This means that for a carbon to be chiral, it must have four distinct substituents.

### Step 2: Identify the smallest alkane
The smallest alkane is methane (CH₄), which has only one carbon atom. However, it does not have a stereogenic center because all four hydrogen atoms are identical.

### Step 3: Move to the next smallest alkanes
The next smallest alkanes are ethane (C₂H₆) and propane (C₃H₈). Ethane has two carbon atoms, and both are bonded to hydrogen atoms, so it also does not have a stereogenic center.

### Step 4: Consider butane (C₄H₁₀)
Butane has four carbon atoms. However, it can be arranged in two forms: n-butane and isobutane (2-methylpropane). Isobutane has a stereogenic center because one of its carbon atoms is bonded to three different groups (a methyl group, an ethyl group, and a hydrogen atom).

### Step 5: Determine the molecular formula
For isobutane (the branched form of butane), the molecular formula is C₄H₁₀. This is the smallest alkane that possesses a stereogenic center.

### Conclusion
The molecular formula for the alkane of smallest molecular weight which possesses a stereogenic center is **C₄H₁₀**.

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