isomer count

Question

Number of structural isomers of C5H12 (pentane) is:

RankGuru · Accepted Answer

1. **Formula**: $C_5H_{12}$ follows the general formula for alkanes ($C_nH_{2n+2}$).
2. **Isomer 1 (Normal)**: $n$-pentane (a continuous chain of 5 carbons).
3. **Isomer 2 (Iso)**: $2$-methylbutane (a 4-carbon chain with a methyl branch on the $2^{nd}$ carbon).
4. **Isomer 3 (Neo)**: $2,2$-dimethylpropane (a central carbon with 4 methyl groups attached; also conceptually a 3-carbon chain with two branches).
5. **Total**: There are exactly **3** structural isomers. Beyond $C_5$, the number of possible isomers increases rapidly.

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isomer count

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