Draw all constitutional isomers with molecular formula C3H8O

Draw all constitutional isomers with molecular formula C3H8O, and rank them in terms of increasing acidity:

The Correct Answer and Explanation is :

The molecular formula C3H8O can represent several constitutional isomers, specifically alcohols and ethers, based on how the atoms are arranged. The isomers with this formula are:

1. Propan-1-ol (n-propyl alcohol): The hydroxyl group (-OH) is attached to the first carbon atom in the chain.
2. Propan-2-ol (isopropyl alcohol): The hydroxyl group is attached to the second carbon atom.
3. Methoxyethane (also known as methyl ether): An ether where the oxygen is attached to a methyl group (-CH3) and an ethyl group (-CH2CH3).

Ranking in terms of increasing acidity:

1. Methoxyethane (methyl ether): Ethers generally have lower acidity because the oxygen atom in the ether is not as electron-withdrawing as in alcohols, and the lack of a free hydroxyl group means it cannot donate a proton (H+).
2. Propan-2-ol (isopropyl alcohol): Alcohols typically have moderate acidity due to the ability of the hydroxyl group to donate a proton. The electron-donating nature of the alkyl group makes it less acidic than some other alcohols, but more acidic than ethers.
3. Propan-1-ol (n-propyl alcohol): This alcohol is slightly more acidic than isopropyl alcohol because of the difference in alkyl group structure. The hydroxyl group is at the end of the chain, and while both alcohols have similar electron-donating alkyl groups, the lack of branching in n-propyl alcohol slightly enhances its ability to stabilize the conjugate base, making it more acidic.

Explanation of Acidity:

Acidity is influenced by the ability of a compound to donate a proton. Alcohols, with their hydroxyl group (-OH), can donate a proton to form an alkoxide ion, whereas ethers lack a hydrogen to donate. The structure of the surrounding groups also affects acidity; for example, branching can reduce the stability of the conjugate base, lowering acidity. In propan-1-ol, the linear structure allows for better stabilization of the conjugate base than in the branched structure of propan-2-ol.

Let me now generate the image of these structures.

Here are the molecular structures for the constitutional isomers of C3H8O: propan-1-ol (n-propyl alcohol), propan-2-ol (isopropyl alcohol), and methoxyethane (methyl ether).

Let me know if you’d like further clarification on their structures or how the ranking of acidity works!