Which of the following molecular formulas corresponds to a cycloalkane?

• A. $C_5{H}_{12}$
• B. $C_5{H}_8$
• C. $C_4{H}_{10}$
• D. $C_5{H}_{10}$

Answer: (D)

Verified step by step guidance

1. Recall the general formula for alkanes, which is \(C_nH_{2n+2}\). These are saturated hydrocarbons with no rings or double bonds.
2. Understand that cycloalkanes have one ring, which reduces the number of hydrogens by 2 compared to the corresponding alkane. Therefore, the general formula for cycloalkanes is \(C_nH_{2n}\).
3. Check each given molecular formula against these formulas: for \(n=5\), the alkane formula is \(C_5H_{12}\), and the cycloalkane formula is \(C_5H_{10}\).
4. Compare the given options: \(C_5H_{12}\) matches the alkane formula, \(C_5H_8\) has fewer hydrogens and likely corresponds to an alkyne or an unsaturated compound, and \(C_4H_{10}\) matches the alkane formula for \(n=4\).
5. Identify that \(C_5H_{10}\) fits the cycloalkane formula \(C_nH_{2n}\) for \(n=5\), indicating it corresponds to a cycloalkane.