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^-

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Chemistry

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28 March, 18:33

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^-

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Answers (1)

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Bishop · Answer 1

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.