Question
An alkane has a molecular mass of 72. Give all the possible structural isomers along with their IUPAC names.
✓
Answer
The general formula of alkanes is $\text{C}_\text{n}\text{H}_{2\text{n}+2}\Rightarrow$ 12 × n + 1 × (2n + 2) = 72 or 12n + 2n + 2 = 72 or n = 5
Thus, the molecular formula of the alkane is $\mathrm{C}_5 \mathrm{H}_{12}$.
Thus, the molecular formula of the alkane is $\mathrm{C}_5 \mathrm{H}_{12}$.
- $\text{CH}_3-\text{CH}_2-\text{CH}_2-\text{CH}_2-\text{CH}_2-\text{CH}_3\\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ _{\text{n-hexane}}$
- $\text{CH}_3-\text{CH}-\text{CH}_2-\text{CH}_2-\text{CH}_3\\ \ \ \ \ \ \ \ \ \ \ \ \ \ |\\ \ \ \ \ \ \ \ \ \ \ \ \ \ \text{CH}_3\\ \ \ \ \ \ \ \ \ \ _{2-\text{methylpentane}}$
- $\text{CH}_3-\text{CH}_2-\text{CH}-\text{CH}_2-\text{CH}_3\\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ |\\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \text{CH}_3\\ \ \ \ \ \ \ \ \ \ \ _{3-\text{methylpentane}}$
- $\text{CH}_3-\text{CH}-\text{CH}-\text{CH}_3\\ \ \ \ \ \ \ \ \ \ \ \ \ \ |\ \ \ \ \ \ \ \ \ \ |\\ \ \ \ \ \ \ \ \ \ \ \ \ \text{CH}_3\ \ \ \ \text{CH}_3\\ \ \ \ \ _{2,\ 3-\text{dimethylbutane}}$
- $ \ \ \ \ \ \ \ \ \ \ \ \ \ \text{CH}_3\\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ |\\\text{CH}_3-\text{C}-\text{CH}_2-\text{CH}_3\\ \ \ \ \ \ \ \ \ \ \ \ \ \ |\\ \ \ \ \ \ \ \ \ \ \ \ \ \text{CH}_3\\ \ \ \ \ \ _{2,\ 2-\text{dimethylbutane}}$
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