The Standard Hydrogen Electrode The absolute value of a half cell potential cannot be measured, only differences in potential between pairs of half-cells. For this reason, it is necessary to have a...
Electrochemical Cells We have seen previously that redox reactions involve simultaneous oxidation and reduction as electrons flow from the reducing agent to the oxidizing agent Which way electrons ...
Acid & Base Calculations pH The acidity of an aqueous solution depends on the number of H3O+ ions in solution pH is defined as: pH = -log [H3O+] Where [H3O+] is the concentration of H3O+ ions i...
Acid & Base Dissociation Constants Weak acids A weak acid is an acid that partially (or incompletely) dissociates in aqueous solutions For example, most carboxylic acids (e.g. ethanoic acid), H...
Salt Hydrolysis An ionic salt is formed from the neutralisation reaction of an acid and base Neutralisation The ionic salt, MA, formed will dissociate in water Hydrolysis is where water is used to...
Buffers A buffer solution is a solution which resists changes in pH when small amounts of acid or base are added A buffer solution is used to keep the pH almost constant A buffer can consist of wea...
Indicators An acid-base indicator is a weak acid which dissociates to give an anion of a different colour Consider a weak acid, HIn: HIn (aq) + H2O (l) ⇌ H3O+ (aq) + In– (aq) colour 1 ...
pH Curves During a titration, a pH meter can be used and a pH curve plotted A pH curve is a graph showing how the pH of a solution changes as the acid (or base) is added The features of a pH curve ...
Lewis Theory of Acids & Bases A more general definition of acids and bases was given by G.N. Lewis who defined them as: A Lewis acid is an electron pair acceptor A Lewis base is an electron pai...
