Acids

• When an acid is added to water, the ion released into the solution is the hydrogen ion (H+)
• An acid is defined as a proton donor
• The dissociation of a strong acid involves full dissociation
• Magnesium hydroxide is the base used to treat acid indigestion
• A base is defined as a proton acceptor
• Alkalis are bases that can dissolve in water to form aqueous hydroxide ions
• Amphoteric substances are substances that can act as both acids and bases
• When acids react with carbonates, the products formed are salt, carbon dioxide, and water
• A salt is a compound formed when the H+ ion of an acid is replaced by a metal ion or positive ion
• When acids react with metal oxides, the products formed are salt and water
• When acids react with alkalis, the products formed are salt and water
• When acids react with metals, the products formed are salt and hydrogen
• The products are the same when acids react with alkalis or metal oxides because both alkalis and metal oxides are types of bases
• Ammonium salts are formed when acids react with aqueous ammonia
• Hydrated crystals are a crystalline structure containing water
• Anhydrous crystals refer to a crystalline form that contains no water
• A dot formula indicates the amount of water present in a crystalline structure
• The methods to carry out a titration include:

  • Using a pipette to measure the volume of a solution
  • Adding the solution into a conical flask and an indicator
  • Adding the other solution into a burette and recording the volume
  • Slowly adding the solution in the burette into the conical flask
  • Swirling the mixture continuously until the end point is reached
  • Repeating until concordant results are obtained
• The color of methyl orange in an acid is red, in a base is yellow, and at the end point is orange
• Tribasic acid

  • H3PO4
• Ion causing a solution to become acidic

  • H+ (hydrogen ion) or H3O+ (oxonium ion)
• Strong acid

  Acids dissociate completely
• Bronsted-Lowry base


  Proton acceptor
• Ion causing a solution to become alkaline


  • -OH (hydroxide ion)
• Lewis base

  Electron pair donor
• Monobasic acid

  • HCl
• Bronsted-Lowry acid


  Proton donor
• What ion causes a solution to be alkaline?
• What ion causes a solution to become acidic? (2 answers)
• Lewis acid

  Electron pair acceptor
• Dibasic acid


  • H2SO4
• Acid base pairs for the reaction CH3COOH + H2O ⇌ CH3COO- + H3O+


  Acid 1: CH3COOH, Base 2: H2O, Base 1: CH3COO-, Acid 2: H3O+
• Ionisation of water

  2H2O (l) ⇌ H3O+ (aq) + -OH (aq) OR H2O (l) ⇌ H+ (aq) + -OH (aq)
• Examples of strong acids

  • Hydrochloric acid, Sulfuric acid, Nitric acid
• Equation to convert pKa into Ka: Ka = 10^(-pKa)
• Symbol of acid dissociation constant is Ka
• Strong acids

  • Hydrochloric acid
  • Sulfuric acid
  • Nitric acid
• Equation to convert concentration of H+ into pH: pH = -log[H+]
• Weak acid

  • Methanoic acid, any organic acid
• Acids dissociate completely