Question

Give the molecular formula of a cyclic alkane, a cyclic alkene, a linear alkyne, and an aromatic hydrocarbon that in each case contains six carbon atoms. Which are saturated and which are unsaturated hydrocarbons?

Short answer

The molecular formulas of the hydrocarbons with six carbon atoms are as follows: Cyclic alkane (cyclohexane) is \(C_6H_{12}\), cyclic alkene (cyclohexene) is \(C_6H_{10}\), linear alkyne (hex-1-yne) is \(C_6H_{10}\), and aromatic hydrocarbon (benzene) is \(C_6H_6\). Cyclic alkane is saturated, while cyclic alkene, linear alkyne, and aromatic hydrocarbon are unsaturated.

Step-by-step solution

1. Molecular Formula of a Cyclic Alkane:

A cyclic alkane is a hydrocarbon where carbon atoms are connected in a closed ring, with each carbon atom forming single bonds with surrounding carbon atoms and hydrogen atoms. The general formula for cyclic alkanes is \(C_nH_{2n}\), where 'n' is the number of carbon atoms. For a cyclic alkane with 6 carbon atoms, we would have: n = 6 Molecular formula = \(C_6H_{2(6)}\) Molecular formula = \(C_6H_{12}\) Cyclohexane is an example of a cyclic alkane with six carbon atoms and the molecular formula \(C_6H_{12}\).

2. Molecular Formula of a Cyclic Alkene:

A cyclic alkene is a hydrocarbon where carbon atoms are connected in a closed ring, with one double bond between two carbon atoms and single bonds between the other carbon and hydrogen atoms. The general formula for cyclic alkenes is \(C_nH_{2n-2}\), given that it possesses only one double bond. For a cyclic alkene with 6 carbon atoms, we would have: n = 6 Molecular formula = \(C_6H_{2(6)-2}\) Molecular formula = \(C_6H_{10}\) Cyclohexene is an example of a cyclic alkene with six carbon atoms and the molecular formula \(C_6H_{10}\).

3. Molecular Formula of a Linear Alkyne:

A linear alkyne is a hydrocarbon where carbon atoms are connected in a straight chain, with one triple bond between two carbon atoms and single bonds between the other carbon and hydrogen atoms. The general formula for alkynes is \(C_nH_{2n-2}\), given that it possesses only one triple bond. For a linear alkyne with 6 carbon atoms, we would have: n = 6 Molecular formula = \(C_6H_{2(6)-2}\) Molecular formula = \(C_6H_{10}\) Hex-1-yne is an example of a linear alkyne with six carbon atoms and the molecular formula \(C_6H_{10}\).

4. Molecular Formula of an Aromatic Hydrocarbon:

An aromatic hydrocarbon is a hydrocarbon with a cyclic ring of carbon atoms connected by alternating single and double bonds, exhibiting resonance stability. The most common aromatic hydrocarbon is benzene. Given that we are looking for an aromatic hydrocarbon with 6 carbon atoms, it would have: Molecular formula = \(C_6H_6\) Benzene is an example of an aromatic hydrocarbon with six carbon atoms and the molecular formula \(C_6H_6\).

5. Saturated and Unsaturated Hydrocarbons:

Saturated hydrocarbons only have single bonds between carbon atoms, while unsaturated hydrocarbons have one or more double or triple bonds between carbon atoms. - Cyclic Alkane (\(C_6H_{12}\)): Saturated - Cyclic Alkene (\(C_6H_{10}\)): Unsaturated - Linear Alkyne (\(C_6H_{10}\)): Unsaturated - Aromatic Hydrocarbon (\(C_6H_6\)): Unsaturated