11.8 Review Questions

According to the Brønsted–Lowry theory, which statement correctly defines an acid, a base, and a proton-transfer reaction?

• An acid is a proton donor, a base is a proton acceptor, and a proton-transfer reaction involves the transfer of a proton from the acid to the base.

• An acid is a proton acceptor, a base is a proton donor, and a proton-transfer reaction involves the transfer of an electron.

• An acid is a substance that increases hydroxide ions, a base increases hydrogen ions, and a proton-transfer reaction involves electron sharing.

• An acid and a base both donate protons, and a proton-transfer reaction involves the loss of neutrons.

A more accurate and precise method to measure the pH of the acid is:

• using a pH meter

• using litmus paper

• using universal indicator paper

• using a color chart

Select the equation that illustrates the amphiprotic nature of H₂O.

• H₂O + HCl → H₃O⁺ + Cl⁻;

  H₂O + NH₃ → OH⁻ + NH₄⁺

• H₂O + NaCl → NaOH + HCl

• H₂O + CO₂ → H₂CO₃

• H₂O + O₂ → H₂O₂

Sulfuric acid is a strong diprotic acid. This means that:

• It completely ionizes in water and can donate two protons (H⁺) per molecule, as shown by the equations: H₂SO₄ → H⁺ + HSO₄⁻ and HSO₄⁻ → H⁺ + SO₄²⁻.

• It only partially ionizes in water and can donate one proton per molecule.

• It does not ionize in water and cannot donate any protons.

• It completely ionizes in water but can only donate one proton per molecule.

To raise the pH of swimming pool water that has a pH of 4.5, you would add:

• an acid

• a base

• chlorine

• salt

5b. The pH should be about 7.5 for best conditions. This solution is:

• acidic

• neutral

• alkaline

• very acidic

6a. Conjugate acid–base pairs are:

• two species that differ by a proton (H⁺)

• two acids that have the same strength

• two bases that have the same strength

• two substances that do not react with each other

• i. HCl ii. HCO₃− iii. H₂SO₄ iv. H₃O+ v. H₂O

• i. HClO₄ ii. H₂CO₃ iii. HSO₄− iv. HO− v. H₂O₂

State the formulas of the conjugate base of the following acids: i. HF ii. HCO₃⁻ iii. HSO₄⁻ iv. H₂O v. H₂S

• i. HF₂⁻ ii. H₂CO₃ iii. HSO₃⁻ iv. H₃O⁺ v. S₂⁻

• i. H⁻ ii. CO₂⁻ iii. SO₄⁻ iv. O₂⁻ v. S⁻

Write equations to show the following: Hydrogen sulfide is a weak diprotic acid.

• H₂S + H₂O ⇌ HS- + H₃O⁺; HS^- + H₂O ⇌ S₂^- + H₃O⁺

• H₂S + O₂ → H₂O + SO₂

• H₂S + 2NaOH → Na₂S + 2H₂O

• H₂S → H₂ + S