Brønsted-Lowry Acids & Bases (College Board AP® Chemistry)

Exam Questions

8 mins8 questions
11 mark

H3NSO3 (aq) + 2NH3 (aq) ⇌ HNSO32- (aq) + 2NH4+ (aq)

For the equilibrium equation shown, which species are Brønsted-Lowry acids?

  • NH4+ and NH3

  • NH4+ and HNSO32-

  • H3NSO3 and HNSO32-

  • H3NSO3 and NH4+

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21 mark

H2PO4(aq) + CN- (aq) ⇌  HCN (aq)  + HPO42− (aq)

What is the conjugate acid in the reaction above?

  • HCN

  • CN-

  • H2PO4

  • HPO42−

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31 mark

H3PO4 (aq) + H2O (l)  ⇌ H2PO4- (aq) + H3O+ (aq)

Consider the reaction above. Which of the following statements is true?

  • H3PO4 and H2PO4- is a base and conjugate acid pair.

  • H2PO4- is a weak base.

  • H2O is acting as Brønsted-Lowry acid.

  • H3O+ is the conjugate base of H2O.

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41 mark

H2SO4 + HNO3 ⇋  H2NO3+ + HSO4-

The reaction above occurs between concentrated sulfuric and nitric acids.

Identify the two species which are acting as Brønsted–Lowry bases.

  • H2NO3+ and HSO4-

  • HNO3 and H2NO3+

  • H2SO4 and HSO4- 

  • HNO3 and HSO4-

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11 mark

H2O (l) + F- (aq) ⇌ HF (aq) + OH- (aq)

H2O (l) + HNO3 (aq) → H3O+ (aq) + NO3- (aq)

H2O (l) + CO2 (g) ⇌ H2CO3 (aq)

H2O (aq) +  NH3 (aq) ⇌ NH4OH (aq) 

Consider the reactions above.

Which of the following statements is true?

  • H2O is shown acting as a Bronsted-Lowry acid only.

  • NO3- is a strong base.

  • H2O acts as a Bronsted-Lowry acid twice.

  • F- and HF are an acid and conjugate base pair.

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21 mark

Potassium hydrogenphosphate has the formula K2HPO4 .

What is the conjugate base of this compound?

  • H2PO4-

  • KHPO42-

  • PO43-

  • KH2PO4

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31 mark

Which of the following is the conjugate base of carbonic acid (H2CO3)?

  • CO32-

  • OH-

  • H3CO3+

  • HCO3-

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41 mark

HBrO (aq) + H2O (l) ⇌ BrO- (aq) + H3O+ (aq)

Which one of the following statements is true about the reaction above?

  • HBrO is the conjugate base of BrO-

  • H3O+ is the conjugate acid of H2O

  • BrO- is the conjugate acid of HBrO

  • There are no conjugate acid-base pairs in the equilibrium

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