Reactivity 3.1 Proton transfer reactions
Reactivity 3.1.1
Understandings: 
  • ​Brønsted–Lowry acid is a proton donor and a Brønsted–Lowry base is a proton acceptor. 
Learning outcomes:
  • Deduce the Brønsted–Lowry acid and base in a reaction.
Additional notes:
  • A proton in aqueous solution can be represented as both H+(aq) and H3O+(aq). The distinction between the terms “base” and “alkali” should be understood.
This video covers Brønsted–Lowry acids and bases. 
Reactivity 3.1.2
Understandings: 
  • A pair of species differing by a single proton is called a conjugate acid–base pair.
Learning outcomes:
  • Deduce the Brønsted–Lowry acid and base in a reaction.
Linking question(s):
  • Structure 2.1 What are the conjugate acids of the polyatomic anions listed in Structure 2.1?
This video covers conjugate acid-bases pairs.
Reactivity 3.1.3
Understandings: 
  • Some species can act as both Brønsted–Lowry acids and bases.
Learning outcomes:
  • Interpret and formulate equations to show acid–base reactions of these species.
Linking question(s):
  • Structure 3.1 What is the periodic trend in the acid–base properties of metal and non-metal oxides?
  • Structure 3.1 Why does the release of oxides of nitrogen and sulfur into the atmosphere cause acid rain?
This video covers amphiprotic species. 
Reactivity 3.1.4
Understandings: 
  • The pH scale can be used to describe the [H+] of a solution: pH = –log10[H+]; [H+] = 10–pH
Learning outcomes:
  • Perform calculations involving the logarithmic relationship between pH and [H+].
Additional information:
  • Include the estimation of pH using universal indicator, and the precise measurement of pH using a pH meter/probe.
  • The equations for pH are given in the data booklet.​
This video covers the pH scale. 
Reactivity 3.1.5
Understandings: 
  • The ion product constant of water, Kw, shows an inverse relationship between [H+] and [OH–]. Kw = [H+] [OH–]
Learning outcomes:
  • Recognize solutions as acidic, neutral and basic from the relative values of [H+] and [OH–].
Additional information:
  • The equation for Kw and its value at 298 K are given in the data booklet.
Linking question(s):
  • Reactivity 2.3 Why does the extent of ionization of water increase as temperature increases?
This video covers the ionic product constant of water, Kw. 
Reactivity 3.1.6
Understandings: 
  • Strong and weak acids and bases differ in the extent of ionisation.
Learning outcomes:
  • Recognise that acid–base equilibria lie in the direction of the weaker conjugate.
Additional information:
  • HCl, HBr, HI, H2SO4 and HCl are strong acids, and group 1 hydroxides are strong bases.
  • The distinction between strong and weak acids or bases and concentrated and dilute reagents should be covered.
Linking question(s):
  • Reactivity 2.3 How would you expect the equilibrium constants of strong and weak acids to compare?
  • Reactivity 1.1 Why does the acid strength of the hydrogen halides increase down group 17?
This video covers strong and weak acids and bases. 
This video covers how to distinguish between strong and weak acids and bases. 
Reactivity 3.1.7
Understandings: 
  • Acids react with bases in neutralisation reactions.
Learning outcomes:
  • Formulate equations for the reactions between acids and metal oxides, metal hydroxides, hydrogencarbonates and carbonates.
Additional information:
  • Identify the parent acid and base of different salts.
  • Bases should include ammonia, amines, soluble carbonates and hydrogencarbonates; acids should include organic acids.
Linking question(s):
  • Reactivity 1.1 Neutralisation reactions are exothermic. How can this be explained in terms of bond enthalpies?
  • Reactivity 3.2 How could we classify the reaction that occurs when hydrogen gas is released from the reaction between an acid and a metal?
This video covers the reactions of acids and bases. 
Reactivity 3.1.8
Understandings: 
  • pH curves for neutralization reactions involving strong acids and bases have characteristic shapes and features.
Learning outcomes:
  • Sketch and interpret the general shape of the pH curve.
Additional information:
  • Interpretation should include the intercept with the pH axis and equivalence point.
  • Only monoprotic neutralization reactions will be assessed.
Linking question(s):
  • Structure 1.4 Why is the equivalence point sometimes referred to as the stoichiometric point?
Video coming soon.