Problem 37 - Chemistry A Molecular Approach

Question

Write the formula for the conjugate base of each acid. a.\( HCl\) b. \(\mathrm{H}_{2} \mathrm{SO}_{3}\) c.\( HCHO _{2}\) d. \(HF\)

Step-by-Step Solution

Answer

The conjugate bases are a) Cl-, b) HSO3-, c) CHO2-, and d) F-.

Step 1: Understanding Acid Conjugate Bases

The conjugate base of an acid is formed by the removal of a proton (H+) from the acid molecule. To write the formula for the conjugate base, remove one hydrogen ion from the chemical formula of the acid.

Step 2: Writing the Conjugate Base for HCl

Remove one hydrogen ion from the hydrochloric acid (HCl) formula to get its conjugate base. The resulting conjugate base is Cl-.

Step 3: Writing the Conjugate Base for H2SO3

Remove one hydrogen ion from the sulfurous acid (H2SO3) formula to get its conjugate base. The resulting conjugate base is HSO3-.

Step 4: Writing the Conjugate Base for HCHO2

Remove one hydrogen ion from the formic acid (HCHO2) formula to get its conjugate base. The resulting conjugate base is CHO2-.

Step 5: Writing the Conjugate Base for HF

Remove one hydrogen ion from the hydrofluoric acid (HF) formula to get its conjugate base. The resulting conjugate base is F-.

Key Concepts

Acid-Base Reaction

An acid-base reaction is a chemical process in which an acid and a base interact, usually resulting in the formation of water and a salt. This reaction is fundamental in chemistry, often showcased in neutralization processes, where the acidic and basic properties of the reactants are diminished or neutralized.

When an acid reacts, it donates a proton (H+), while the base accepts it, and this interaction defines the transformation of species within the reaction mixture. For instance, when hydrochloric acid (HCl) reacts with a base like sodium hydroxide (NaOH), water (H2O) and sodium chloride (NaCl) are produced. Such interactions highlight the dynamic nature of proton transfer and acid-base chemistry.

Proton Transfer

Proton transfer is the cornerstone of acid-base chemistry and involves the movement of a proton from an acid to a base. A crucial concept is the Brønsted-Lowry theory, which defines acids and bases in terms of their ability to donate or accept protons, respectively.

The act of proton transfer is what changes an acid into its conjugate base, a less acidic species that remains after the acid has donated a proton. For instance, when the acid H2SO3 loses a proton, it transforms into its conjugate base, HSO3-. This change indicates the acid's proclivity to release a proton, and the remaining structure's potential to either take back that proton or act as a base in subsequent reactions.

Chemical Formula

Chemical formulas represent the composition of a substance with atomic symbols and indicate the number of atoms of each type present in the compound. It's a concise way for scientists to transmit detailed information about the substance's makeup. An acid's chemical formula is critical when determining the formula of its conjugate base.

For example, formic acid has the chemical formula HCHO2, which succinctly displays all elements and their quantities in the molecule. To find its conjugate base, simply remove a proton, resulting in the base CHO2-. This new formula signifies a different entity with properties distinct from the original acid, representing not just a physical alteration but a functional transformation as well, capable of participating in unique chemical reactions.