Module 6.1 Properties of Acids and Bases

Which of the following is an Arrhenius base?

• Na

• NaOH

• Na₂CO₃

• NaHCO₃

Which indicator would be best for distinguishing between a face cleanser (pH =5.0) and a soap (pH = 9.0)?

• Bromophenol blue (colour change: yellow-blue, pH range: 3.0-4.6)

• Methyl orange (colour change: red-yellow, pH range: 3.1-4.4)

• Phenol red (colour change: yellow-red, pH range: 6.4-8.0)

• Thymolphthalein (colour change: colourless-blue, pH range: 9.4-10.6)

Equimolar solutions of NaCl(aq), NH₄Cl(aq) and NaCH₃COO(aq) were prepared.

In which of the following are these salt solutions listed from least to most acidic?

• NaCl(aq), NH₄Cl(aq), NaCH₃COO(aq)

• NaCl(aq), NaCH₃COO(aq), NH₄Cl(aq)

• NH₄Cl(aq), NaCl(aq), NaCH₃COO(aq)

• NaCH₃COO(aq), NaCl(aq), NH₄Cl(aq)

Which of the following is NOT a Brønsted–Lowry reaction?

• NH₄⁺ + NH₂^– ↔ 2NH₃

• CO₂ + OH^– ↔ HCO₃^–

• HClO₄ + CH₃COOH ↔ CH₃COOH₂⁺ + ClO₄^–

• CH₃CH₂O^– + CH₃NH₃⁺ ↔ CH₃CH₂OH + CH₃NH₂

Which of the following compounds can be correctly described as an Arrhenius base when dissolved in water?

• Sodium nitrate

• Sodium sulfate

• Sodium chloride

• Sodium hydroxide

An aqueous solution of an unknown acid (HA) is represented in the image.

Which option best describes this solution?

• Strong: ✓

  Concentrated: ✓

• Strong: ✓

  Concentrated: X

• Strong: X

  Concentrated: ✓

• Strong: X

  Concentrated: X