Benzoic acid (C6 H5 COOH) and aniline (C6 H5 NH2) are both derivatives of benzene. Benzoic acid

step 1 Option A, we have the conjugate base of benzoic acid. So the conjugate base of benjoic acid is f

Benzoic acid (C6 H5 COOH) and aniline (C6 H5 NH2) are both...

Benzoic acid $\left(\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{COOH}\right)$ and aniline $\left(\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{NH}_{2}\right)$ are both derivatives of benzene. Benzoic acid is an acid with $K_{a}=6.3 \times 10^{-5}$ and aniline is a base with $K_{a}=4.3 \times 10^{-10}$ (a) What are the conjugate base of benzoic acid and the conjugate acid of aniline? (b) Anilinium chloride $\left(\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{NH}_{3} \mathrm{Cl}\right)$ is a strong electrolyte that dissociates into anilinium ions $\left(\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{NH}_{3}^{+}\right)$ and chloride ions. Which will be more acidic, a $0.10 \mathrm{M}$ solution of benzoic acid or a 0.10 $M$ solution of anilinium chloride? (c) What is the value of the equilibrium constant for the following equilibrium?

Key Concepts

Acid and Base Strength

Acid strength is described by the acid dissociation constant (Ka), which quantifies how easily an acid donates its proton. Similarly, the strength of a base is often characterized by its conjugate acid’s Ka or by its base dissociation constant (Kb). Comparing these constants provides insight into which species is more likely to donate or accept a proton. This concept underpins the interpretation of equilibrium positions in acid–base reactions.

Electrolyte Dissociation

This concept refers to the process by which compounds split into ions when dissolved in water. Strong electrolytes dissociate completely, meaning their ions are fully available in solution. Recognizing the extent of electrolyte dissociation is essential for understanding the concentration of reactive species in a solution, which in turn affects the acidity or basicity of that solution.

Conjugate Acid-Base Pairs

This concept involves understanding that when an acid donates a proton it forms its conjugate base, and when a base accepts a proton it forms its conjugate acid. The idea is central to acid–base chemistry and helps in predicting the direction of acid–base reactions as well as the strengths of the resultant species. Recognizing conjugate pairs allows one to relate the properties of acids and bases through the equilibrium constants of their respective reactions.

Equilibrium Constant Relationships

The equilibrium constant quantitatively describes the ratio of product concentrations to reactant concentrations at equilibrium for a given chemical reaction. In acid–base chemistry, relationships such as Kw = Ka × Kb (for a conjugate acid–base pair) are fundamental. Understanding these relationships allows one to calculate unknown equilibrium constants from related known constants, and they are integral to predicting the behavior of chemical systems under equilibrium conditions.

Transcript

Please give Ace some feedback