The following compounds can all react as acids.

c. Rank the original compounds in order, from strongest acid to weakest acid.

Verified step by step guidance

1. Identify the functional groups in each compound: CH3COOH, CF3COOH, CF3CH2COOH, and CH3CH2OH. The first three are carboxylic acids, and the last one is an alcohol.
2. Understand that the acidity of a compound is influenced by the stability of its conjugate base. A more stable conjugate base corresponds to a stronger acid.
3. Consider the effect of electronegative substituents on acidity. Electronegative groups, like CF3, can stabilize the conjugate base through inductive effects, increasing acidity.
4. Rank the compounds based on the presence and position of electronegative groups: CF3COOH has the strongest electron-withdrawing group directly attached to the carboxyl group, making it the strongest acid.
5. Compare the remaining compounds: CF3CH2COOH is next due to the electron-withdrawing effect of CF3, followed by CH3COOH, and finally CH3CH2OH, which is the weakest acid due to the lack of electron-withdrawing groups and being an alcohol.

Key Concepts

Acidity and pKa

Acidity refers to the ability of a compound to donate a proton (H+) in a chemical reaction. The strength of an acid is often measured by its pKa value; lower pKa values indicate stronger acids. Understanding the relationship between structure and acidity is crucial for ranking acids, as factors like electronegativity and resonance can significantly influence a compound's ability to stabilize the negative charge after deprotonation.

Inductive Effect

The inductive effect describes how the presence of electronegative atoms or groups in a molecule can influence the acidity of nearby protons. Electronegative atoms, such as fluorine, can withdraw electron density through sigma bonds, stabilizing the negative charge on the conjugate base formed after deprotonation. This effect is particularly important in determining the relative acidity of compounds with different substituents.

Resonance Stabilization

Resonance stabilization occurs when a molecule can distribute its electron density across multiple structures, leading to increased stability of the conjugate base. In the context of acidity, compounds that can delocalize the negative charge through resonance after losing a proton will generally be stronger acids. Recognizing which structures can participate in resonance is essential for ranking the acidity of the given compounds.