Acids and Bases Definitions Quiz

Arrhenius Definition of Acids and Bases

• Arrhenius acids release hydrogen ions (H+) or hydronium ions (H3O+) in solution.
• H+ ions in water are associated with water molecules to form hydronium ions (H3O+).
• Examples of Arrhenius acids: HF (hydrofluoric acid), HCl (hydrochloric acid), H2SO4 (sulfuric acid), HNO3 (nitric acid).
• Arrhenius bases release hydroxide ions (OH-) in solution.
• Arrhenius acid donate H+ ions to water creating hydronium ions (H3O+) and their conjugate base.
• Arrhenius bases dissociate in water to produce metal ions and hydroxide ions (OH-).
• Examples of Arrhenius bases: NaOH (sodium hydroxide), KOH (potassium hydroxide), Ca(OH)2 (calcium hydroxide).

Brønsted-Lowry Definition of Acids and Bases

• Brønsted-Lowry acids are proton (H+) donors.
• Brønsted-Lowry bases are proton (H+) acceptors.
• When an acid donates a proton, it forms its conjugate base.
• When a base accepts a proton, it forms its conjugate acid.
  • To find the conjugate acid: Add one hydrogen and increase the charge by one.
  • To find the conjugate base: Remove one hydrogen and decrease the charge by one.
• Examples of Brønsted-Lowry acid-base reactions:
  • HF (hydrofluoric acid) + H2O (water) → H3O+ (hydronium ion) + F- (fluoride ion)
    • HF is the Brønsted-Lowry acid (proton donor)
    • H2O is the Brønsted-Lowry base (proton acceptor)
    • H3O+ is the conjugate acid of H2O
    • F- is the conjugate base of HF
  • CO32- (carbonate ion) + H2O (water) → HCO3- (bicarbonate ion) + OH- (hydroxide ion)
    • H2O is the Brønsted-Lowry acid (proton donor)
    • CO32- is the Brønsted-Lowry base (proton acceptor)
    • HCO3- is the conjugate acid of CO32-
    • OH- is the conjugate base of H2O

Lewis Definition of Acids and Bases

• Lewis acids are electron pair acceptors.
• Lewis bases are electron pair donors.
• Lewis acids often have an incomplete octet and can accept electron pairs.
• Lewis bases have lone pairs of electrons they can donate.
• Lewis base is also known as a nucleophile (electron-rich).
• Lewis acid is also known as an electrophile (electron-poor).
• Example of a Lewis acid-base reaction:
  • BH3 (borane) + NH3 (ammonia) → BH3-NH3 (ammonia-borane adduct)
    • BH3 is the Lewis acid (electron pair acceptor)
    • NH3 is the Lewis base (electron pair donor)
    • The nitrogen atom in NH3 donates a lone pair of electrons to the empty orbital on boron in BH3.

Key Concepts

• Conjugate acid: the species formed when a base accepts a proton.
• Conjugate base: the species formed when an acid donates a proton.
• Nucleophile: an electron-rich species attracted to electron-poor centers, typically a Lewis base.
• Electrophile: an electron-poor species attracted to electron-rich centers, typically a Lewis acid.

Test your knowledge on the definitions of acids and bases according to Arrhenius, Brønsted-Lowry, and Lewis theories. This quiz covers key concepts including ion release, proton donation, and electron pair acceptance. Understand the differences and examples of each type.