Question

Which of the following, if any, are not alcohols derived from the methane series of hydrocarbons: \(\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{OH}, \mathrm{C}_{17} \mathrm{H}_{33} \mathrm{OH}\), \(\mathrm{C}_{4} \mathrm{H}_{8} \mathrm{OH}, \mathrm{C}_{9} \mathrm{H}_{19} \mathrm{OH} ?\)

Short answer

The compounds \(\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{OH}, \mathrm{C}_{17} \mathrm{H}_{33} \mathrm{OH}\), and \(\mathrm{C}_{4} \mathrm{H}_{8} \mathrm{OH}\) are not alcohols derived from the methane series of hydrocarbons, while \(\mathrm{C}_{9} \mathrm{H}_{19} \mathrm{OH}\) is derived from the methane series.

Step-by-step solution

Identify the Alkane Series Formula

The general formula for the alkane series of hydrocarbons is \(\mathrm{C}_n\mathrm{H}_{2n + 2}\). Since we are looking for alcohols derived from the methane series, we need to add an \(\mathrm{OH}\) group to the general formula, making it \(\mathrm{C}_n\mathrm{H}_{2n + 1}\mathrm{OH}\). Now, we'll compare each given compound to this general formula.

Analyze Compound 1 (\(\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{OH}\))

First, let's analyze \(\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{OH}\). For this compound, we plug in \(n = 6\) into the general formula \(\mathrm{C}_n\mathrm{H}_{2n + 1}\mathrm{OH}\). We get the formula \(\mathrm{C}_6\mathrm{H}_{2(6) + 1}\mathrm{OH}\), which simplifies to \(\mathrm{C}_6\mathrm{H}_{13}\mathrm{OH}\). Since this is not the same as the given compound, \(\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{OH}\) is not derived from the methane series of hydrocarbons.

Analyze Compound 2 (\(\mathrm{C}_{17} \mathrm{H}_{33} \mathrm{OH}\))

Next, let's analyze \(\mathrm{C}_{17} \mathrm{H}_{33} \mathrm{OH}\). For this compound, we plug in \(n = 17\) into the general formula \(\mathrm{C}_n\mathrm{H}_{2n + 1}\mathrm{OH}\). We get the formula \(\mathrm{C}_{17}\mathrm{H}_{2(17) + 1}\mathrm{OH}\), which simplifies to \(\mathrm{C}_{17}\mathrm{H}_{35}\mathrm{OH}\). Since this is not the same as the given compound, \(\mathrm{C}_{17} \mathrm{H}_{33} \mathrm{OH}\) is not derived from the methane series of hydrocarbons.

Analyze Compound 3 (\(\mathrm{C}_{4} \mathrm{H}_{8} \mathrm{OH}\))

Now, let's analyze \(\mathrm{C}_{4} \mathrm{H}_{8} \mathrm{OH}\). For this compound, we plug in \(n = 4\) into the general formula \(\mathrm{C}_n\mathrm{H}_{2n + 1}\mathrm{OH}\). We get the formula \(\mathrm{C}_4\mathrm{H}_{2(4) + 1}\mathrm{OH}\), which simplifies to \(\mathrm{C}_4\mathrm{H}_{9}\mathrm{OH}\). Since this is not the same as the given compound, \(\mathrm{C}_{4} \mathrm{H}_{8} \mathrm{OH}\) is not derived from the methane series of hydrocarbons.

Analyze Compound 4 (\(\mathrm{C}_{9} \mathrm{H}_{19} \mathrm{OH}\))

Finally, let's analyze \(\mathrm{C}_{9} \mathrm{H}_{19} \mathrm{OH}\). For this compound, we plug in \(n = 9\) into the general formula \(\mathrm{C}_n\mathrm{H}_{2n + 1}\mathrm{OH}\). We get the formula \(\mathrm{C}_9\mathrm{H}_{2(9) + 1}\mathrm{OH}\), which simplifies to \(\mathrm{C}_9\mathrm{H}_{19}\mathrm{OH}\). Since this is the same as the given compound, \(\mathrm{C}_{9} \mathrm{H}_{19} \mathrm{OH}\) is derived from the methane series of hydrocarbons.

Conclusion

Out of the given compounds, \(\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{OH}, \mathrm{C}_{17} \mathrm{H}_{33} \mathrm{OH}\), and \(\mathrm{C}_{4} \mathrm{H}_{8} \mathrm{OH}\) are not alcohols derived from the methane series of hydrocarbons. Only \(\mathrm{C}_{9} \mathrm{H}_{19} \mathrm{OH}\) is derived from the methane series of hydrocarbons.

Key concepts

Methane Series

Alkanes belong to a significant class of hydrocarbons known as the methane series. Alkanes have the simplest form of hydrocarbons. They're made up of single-bonded carbon and hydrogen atoms. The general formula for these hydrocarbons is \(\mathrm{C}_n\mathrm{H}_{2n+2}\). This means each molecule has twice as many hydrogen atoms as the number of carbons, plus two additional hydrogens.

These compounds are called saturated hydrocarbons because they contain the maximum amount of hydrogen possible. Some common examples include methane \(\mathrm{CH}_4\), ethane \(\mathrm{C}_2\mathrm{H}_6\), and propane \(\mathrm{C}_3\mathrm{H}_8\).

Alkanes like these form an important framework in organic chemistry, serving as the base structure upon which many derivatives are formed.

Hydrocarbon Derivatives

In organic chemistry, discovering derivatives of hydrocarbons is intriguing and useful. A derivative is formed when different atoms or groups replace hydrogen atoms in a hydrocarbon.

The main types of derivatives include:

• Alkyl halides: where halogens replace hydrogen.
• Alcohols: where hydroxyl \(\mathrm{OH}\) groups replace hydrogen.
• Aldehydes and ketones: which contain carbonyl groups \(\mathrm{C}=\mathrm{O}\).
• Carboxylic acids: characterized by carboxyl groups \(\mathrm{COOH}\).

Every tiny change in structure can lead to new properties, making derivatives vastly significant in medical, industrial, and environmental applications. Let's take alcohols, for example. These are key players as solvents, fuels, and in producing other chemicals.

Alcohol Classification

Alcohols are classified based on the hydroxyl group \(\mathrm{OH}\) bonded to the carbon chain. They can be simple or more complex depending on the number of carbon atoms and the bonding pattern.

**Primary, Secondary, and Tertiary Alcohols:**

• Primary Alcohols: The \(\mathrm{OH}\) group is attached to a carbon that is bonded to only one other carbon atom. For example, methanol \(\mathrm{CH}_3\mathrm{OH}\) and ethanol \(\mathrm{C}_2\mathrm{H}_5\mathrm{OH}\) are primary alcohols.
• Secondary Alcohols: Here, the carbon with the \(\mathrm{OH}\) group is connected to two other carbons. An example is isopropanol \(\mathrm{C}_3\mathrm{H}_7\mathrm{OH}\).
• Tertiary Alcohols: In these molecules, the carbon attached to the \(\mathrm{OH}\) group is bonded to three other carbon atoms, such as tert-butanol \(\mathrm{C}_4\mathrm{H}_9\mathrm{OH}\).

Each classification imparts different chemical reactivity and physical properties, crucial for designing specific applications in industries, such as making polymers or as de-icing agents.