The acid dissociation constant K_a equals 1.26 × 10^-2 for HSO₄^-and is 5.6 × 10^-10for NH₄⁺. Which statement about the following equilibrium is correct?
HSO₄^-(aq) + NH₃(aq) SO₄^2-(aq) + NH₄⁺(aq)

Question

The acid dissociation constant K_a equals 1.26 × 10^-2 for HSO₄^-and is 5.6 × 10^-10for NH₄⁺. Which statement about the following equilibrium is correct?
HSO₄^-(aq) + NH₃(aq)

The acid dissociation constant K<sub>a</sub> equals 1.26 × 10<sup>-2</sup> for HSO<sub>4</sub><sup>- </sup>and is 5.6 × 10<sup>-10 </sup>for NH<sub>4</sub><sup>+</sup>. Which statement about the following equilibrium is correct? HSO<sub>4</sub><sup>-</sup>(aq) + NH<sub>3</sub>(aq) SO<sub>4</sub><sup>2-</sup>(aq) + NH<sub>4</sub><sup>+</sup>(aq) A) The reactants will be favored because ammonia is a stronger base than the sulfate anion. B) The products will be favored because the hydrogen sulfate ion is a stronger acid than the ammonium ion. C) Neither reactants nor products will be favored because all of the species are weak acids or bases. D) The initial concentrations of the hydrogen sulfate ion and ammonia must be known before any prediction can be made. E) This reaction is impossible to predict, since the strong acid and the weak base appear on the same side of the equation.

SO₄^2-(aq) + NH₄⁺(aq)

Quizplus · Accepted Answer

The equilibrium constant, K, can be calculated as follows:
K = [HSO4-][NH3] / [HSO3-][NH4+]
The higher the value of K, the more likely the products are favored. Comparing the values of the acid dissociation constants for the two acids (K for HSO4- is greater than K for HSO3-), it can be concluded that HSO4- is a stronger acid and NH3 is a stronger base than HSO3- and NH4+, respectively. Therefore, the numerator of the equilibrium constant (which contains the stronger acid and stronger base) will be larger than the denominator, indicating that the products will be favored. Hence, choice B is correct.

The Acid Dissociation Constant Ka Equals 1

The Acid Dissociation Constant K_a Equals 1