N -coproic acid, C5 H11 COOH, found in coconut and palm oil...

$n$ -coproic acid, $\mathrm{C}_{5} \mathrm{H}_{11} \mathrm{COOH}$, found in coconut and palm oil is used in making artificial flavours, has solubility in water equal to $11.6 \mathrm{~g} / \mathrm{L}$. The saturated solution has $\mathrm{pH}=3.0$. The $K_{\mathrm{a}}$ of acid is (a) $10^{-6}$ (b) $10^{-5}$ (c) $2 \times 10^{-5}$ (d) $2 \times 10^{-6}$

$n$ -coproic acid, $\mathrm{C}_{5} \mathrm{H}_{11} \mathrm{COOH}$, found in coconut and palm oil is used in making artificial flavours, has solubility in water equal to $11.6 \mathrm{~g} / \mathrm{L}$. The saturated solution has $\mathrm{pH}=3.0$. The $K_{\mathrm{a}}$ of acid is
(a) $10^{-6}$
(b) $10^{-5}$
(c) $2 \times 10^{-5}$
(d) $2 \times 10^{-6}$

Key Concepts

Solubility in Saturated Solutions

Solubility refers to the maximum amount of a substance that can dissolve in a solvent at a given temperature, resulting in a saturated solution. For weak acids, the solubility can provide the total concentration available in the system, from which the fraction dissociated (and the corresponding pH) can be used to determine equilibrium constants like Ka.

Weak Acid Equilibrium

In a weak acid equilibrium, the acid only partially dissociates into its conjugate base and hydrogen ions in solution. This equilibrium allows for the calculation of the acid dissociation constant (Ka) by considering both the initial concentration of the acid and the concentration of ions produced, which is often inferred from pH measurements.

Acid Dissociation Constant (Ka)

The acid dissociation constant quantifies the propensity of a weak acid to donate a proton in an aqueous solution. It is defined by the equilibrium expression where the product of the concentrations of the ionized species is divided by the concentration of the undissociated acid. This constant is central to understanding the strength and behavior of weak acids in solution.

pH and Hydrogen Ion Concentration

pH is a measure of the acidity or basicity of an aqueous solution, defined as the negative logarithm of the hydrogen ion concentration. It directly reflects the degree of acid dissociation in a solution and is used to relate the measurable acidity (via pH) to the concentrations of species in equilibrium.

Transcript

Please give Ace some feedback