Question

H A and H B are both weak acids in water, and HA is a stronger acid than HB. Which of the following statements is correct? Select one: a. B is a stronger base than A^-, which is a stronger base than H_2O, which is a stronger base than CI^-. b. B is a stronger base than A^-, which is a stronger base than CI^-, which is a stronger base than H_2O. c. None of these (A-D) is correct. d. CI^- is a stronger base than A^-, which is a stronger base than B^-, which is a stronger base than H_2O e. A^- is a stronger base than B^-, which is a stronger base than H_2O, which is a stronger base than CI^-

Answer 1

Answer:

B is a stronger base than A^-, which is a stronger base than H2O, which is a stronger base than CI^-

Explanation:

The general equation for each acid is:

HA(aq) + H2O(ac) ⇄ H3O+(aq) + A-(aq)

HB(aq) + H2O(ac) ⇄ H3O+(aq) + B-(aq)

When these acids dissociate into its ions in water they lose a proton (H+), so they are proton donors (acids) and H2O is the proton acceptor (base). This reaction produces a conjugate acid and a conjugate base.

Conjugate base is what remains of the acid molecule after it loses a proton:

HA = acid         A- Conjugate base

HB = acid         B- Conjugate base

A conjugate acid is formed when the proton is transferred to the base

H2O = base                H3O+ = Conjugate acid

The stronger acid will produce a weaker base. According to this, if HA is a stronger acid than HB, A- would be the weaker base (B- is the stronger base).

Compared with water, A- and B- are stronger bases because when they compete for a proton they have much greater affinity for H+ than water does and the equilibrium position will lie far to the left. (HA and HB are weak acids)

Finally Cl- is the weakest base because it comes after dissociation of HCl which is a strong acid

HCl(aq) + H2O → H3O+(aq) + Cl-(aq)

Note there is no double arrows, equilibrium lies far to the right. A strong acid yields a weak conjugate base it means one that has a low affinity for a proton.