Which of the following compounds is a straight-chain alkane?

A straight-chain alkane is defined as a saturated hydrocarbon with carbon atoms arranged in an unbranched chain, adhering to the general formula CₙH₂ₙ₊₂.

In this case, the compound C₃H₈ corresponds to three carbon atoms. To verify if it fits the definition of a straight-chain alkane, we can apply the formula: CₙH₂ₙ₊₂, where "n" is the number of carbon atoms.

For C₃H₈, setting n=3 results in:

• Number of Hydrogens = 2(3) + 2 = 6 + 2 = 8

Since C₃H₈ has exactly eight hydrogen atoms, it satisfies the alkane formula and thus is a straight-chain alkane with the structure of propane.

The other compounds do not meet the criteria for straight-chain alkanes or do not conform to the alkane formula. C₄H₈, which has a molecular formula suggesting it could be an alkene or cycloalkane, has two fewer hydrogens than required for a saturated alkane structure. C₄H₇ also cannot be an alk