Lectures on pH calculation
On all pages HA, H2A, H3A denote acids, while BOH, B(OH)2, B(OH)3 bases.
C is for analytical concentration. Ca and Cb stand for analytical concentrations of acid and base respectively. Square brackets denote equilibrium concentration of individual forms.
Ka stands for acid dissociation constant, Ka1, Ka2 stand for stepwise dissociation constants, while Ka12 or Ka123 stand for overall dissociation constants. Kb is base dissociation constant - with all identical modifiers.
KaBOH and KbHA are dissociation constants for conjugate base and acid respectively used whenever I thought there is a risk of confusion.
M stands for mol/L.
log stands always for logarithm base 10.
I am assuming that you are familiar with quadratic equations and your knowledge about logarithms reaches a little bit further than the key on your calculator.