Question

Draw all the isomers of the alcohols having the molecular formula \(\mathrm{C}_{4} \mathrm{H}_{10} \mathrm{O}\).

Short answer

The isomers of the alcohols with the molecular formula C4H10O are: 1. 1-Butanol: \(CH_{3}-CH_{2}-CH_{2}-CH_{2}-OH\) 2. 2-Butanol: \(CH_{3}-CH_{2}-CH(OH)-CH_{3}\) 3. 2-Methyl-2-propanol: \(CH_{3}-C(CH_{3})_{2}-OH\) These isomers are generated by considering different carbon chain possibilities and attaching the hydroxyl (OH) group in various positions.

Step-by-step solution

Write down the carbon chain possibilities.

As there are 4 carbons in the molecular formula, we have the following carbon chain possibilities: 1. Butane (Straight chain): *C-C-C-C* 2. Isobutane (Branched): *C-C-C* | *C*

Generate the positional isomers of alcohols.

From the carbon chains mentioned in Step 1, we will now try to position the hydroxyl (OH) group: For Butane: 1. *C-C-C-C* 2. *C-C-C-C* First isomer: Attach the OH group on the first carbon in the straight chain. Second isomer: Attach the OH group on the second carbon in the straight chain. For Isobutane: 1. *C-C-C* | *C* Only one isomer is possible: Attach the OH group on the second carbon in the branched chain.

Draw the structural formulas of the isomers.

Now, we will draw the structural formulas for the isomers of C4H10O. 1. For the first isomer (1-Butanol): \[CH_{3}-CH_{2}-CH_{2}-CH_{2}-OH\] 2. For the second isomer (2-Butanol): \[CH_{3}-CH_{2}-CH(OH)-CH_{3}\] 3. For the third isomer (2-Methyl-2-propanol): \[CH_{3}-C(CH_{3})_{2}-OH\] These are all the possible isomers of the alcohols having the molecular formula C4H10O.

Key concepts

Molecular Formula

Understanding molecular formulas is the first step to determining possible isomers. A molecular formula indicates the number and type of atoms present in a molecule. For the alcohols in this exercise, the formula given is \( C_4H_{10}O \). This tells us the compound contains 4 carbon atoms, 10 hydrogen atoms, and one oxygen atom.
A single molecular formula can represent several different molecules, known as isomers, which have different arrangements of atoms. This concept is crucial because, even with the same count of each element, different positions or structures can create unique compounds.

Carbon Chain

When considering isomers, especially for organic compounds like alcohols, the carbon chain forms the backbone of the molecule. The carbon chain represents a series of connected carbon atoms.
For \( C_4H_{10}O \), there are two main carbon chain arrangements:

• Butane: A straight chain where all four carbon atoms are connected in a linear sequence.
• Isobutane: A branched chain which features a central carbon atom bonded to three others.

The carbon chain variations play a significant role in determining the physical and chemical properties of the isomers.

Positional Isomers

Positional isomers are types of structural isomers where the functional group, such as the hydroxyl group in alcohols, is placed in different positions on the carbon chain.
In the case of \( C_4H_{10}O \), for the straight chain butane, the hydroxyl group can be attached either to the first carbon, forming 1-butanol, or to the second carbon, creating 2-butanol.
For the branched chain isobutane, the hydroxyl group attaches uniquely to create a distinctive isomer known as 2-Methyl-2-propanol. Positional isomerism introduces variability in chemistry by altering the connectivity of atoms without changing the overall formula.

Structural Formulas

A structural formula visually depicts how atoms are arranged in a molecule. For the isomers of \( C_4H_{10}O \), structural formulas help us understand their unique arrangements.

• 1-Butanol: The structural formula is \( CH_3-CH_2-CH_2-CH_2-OH \). The OH group is attached at the end of a linear chain.
• 2-Butanol: Here, it’s \( CH_3-CH_2-CH(OH)-CH_3 \), with the OH group placed on the second carbon of a straight chain.
• 2-Methyl-2-propanol: Represented as \( CH_3-C(CH_3)_2-OH \), where the OH is on the central carbon of a branched chain. The branched nature creates a different chemical identity than the straight chains.

Drawing structural formulas provides clarity on the specific configuration of each isomer, aiding in the visualization and understanding of their distinct properties.