Acid and Bases

Which of the following statements does not support Arrhenius’ work with acids and bases?

• a. Arrhenius discovered that all acidic and basic solutions he tested were electrolytes.

• b. He determined that acids and bases must ionize or dissociate in water.

• c. According to Arrhenius, an acid is defined as a hydrogen-containing compound that ionizes to yield hydrogen ions (H+ ) dissolved in aqueous solution.

• d. According to Arrhenius, an acid is defined as a compound that ionizes to yield hydroxide ions (OH- ) in aqueous solution.

Which of the following is considered a limitation of the Brønsted—Lowry definition of acids and bases?

• a. The Brønsted—Lowry theory expands the definition of an acid and base to a proton donor or acceptor.

• b. Even though acids and bases can occur without water, there is still a requirement for the presence of a solvent.

• c. The Brønsted—Lowry theory cannot explain why some substances without hydroxides, like ammonia, can act as bases.

• d. The Brønsted—Lowry theory does not explain how substances without protons can act as acids.

Which of these descriptions is not a characteristic of the Lewis theory?

• a. This theory limits the number of compounds called acids, since any compound that has one or more valence shell orbitals cannot act as an acid.

• b. The Lewis definition is so general that any reaction in which a pair of electrons is transferred becomes an acid-base reaction.

• c. Lewis acid-base reactions include many reactions that would not be included with the Brønsted—Lowry definition.

• d. The Lewis acid-base theory does not affect Brønsted—Lowry bases because any Brønsted—Lowry base must have a pair of non-bonding electrons in order to accept a proton

At 25°C, the concentrations of the hydronium and hydroxide ions in water are equal at

• a. 1.0 x 10⁷ mol/L

• b. 1.0 x 10¹⁴ mol/L

• c. 1.0 x 10^-7 mol/L

• d. 1.0 x 10-¹⁴ mol/L

Which statement regarding indicators is false?

• a. They are strong, organic acids that change colour when the hydronium or hydroxide ion concentration is changed.

• b. Indicators change colour over a given pH range (the colour of each indicator can be coordinated with the pH).

• c. The colour of the indicator can be compared to a standard to determine the pH of the solution.

• d. Using an indicator is not as accurate as a pH metre.

All of these are examples of strong acids with the exception of

• a. HClO₄ (perchloric acid)

• b. HI (hydroiodic acid)

• c. HBr (hydrobromic acid)

• d. H₂CO₃ (carbonic acid)

A carefully controlled neutralization reaction is also known as a/an

• a. oxidation

• b. reduction

• c. titration

• d. dissociation

On a titration curve, what indicates when neutralization of the unknown has occurred?

• a. The beginning of the horizontal region in the acid pH range.

• b. The beginning of the horizontal region in the basic pH range.

• c. The point halfway on the vertical region of the graph.

• d. The beginning of the vertical region of the graph.

All of the following salts are BASIC in water with the exception of

• a. sodium nitrate (NaNO₃)

• b. sodium acetate (NaC₂H₃O₂)

• c. potassium phosphate (K₃PO₅)

• d. sodium sulfide (Na₂S)

Identify the acid, base, conjugate acid, and conjugate base in the following reversible reaction.

HF_(aq) + HSO₃^- _(aq) ↔ F^- _(aq) + H₂SO_3(aq)