Chemistry · Ch 8 — Ionic Equilibrium
Introduction
Introduction
Class XI introduced chemical equilibrium in general. This unit narrows the focus to ionic equilibria -- specifically the equilibria acids and bases set up in solution -- and it isn't just textbook chemistry: several vital processes inside your own body run on aqueous equilibria, such as the carbonic acid-bicarbonate buffer that keeps your blood's pH steady.
What this unit sets out to do. By the end of it you should be able to:
- classify substances into acids and bases using the Arrhenius, Lowry-Bronsted and Lewis concepts;
- define the pH scale, and establish the relationship between pH and pOH;
- describe the equilibrium involved in the ionisation of water;
- explain Ostwald's dilution law, and derive the relationship between a weak electrolyte's dissociation constant and its degree of dissociation;
- recognise the common ion effect, and explain how buffer action works;
- apply the Henderson equation to prepare a buffer solution;
- calculate the solubility product, and relate it to solubility;
- solve numerical problems involving ionic equilibria.
Note
Peter Debye won the 1936 Nobel Prize in Chemistry for his work on molecular structure via dipole moments and X-ray diffraction -- and his broader contributions to the theory of electrolyte solutions underpin much of how this unit treats ions behaving in solution.