A question relating to equilibrium concentrations for weak acids?
Basically, I need an explanation of what's going on here. It's a part of a chapter that explains the concept of dissocation constants for acids and bases.
Consider a weak acid HX that is partially ionized in the aqueous solution. The equilibrium can be expressed by:
HX (aq) + H2O (l) <----> H3O+ (aq) + X- (aq)
If the initial concentration of the acid is "c", and "α" is the extent of ionization, after dissociation of the acid, at equilibrium, the equilibrium concentration of the acid HX is c-cα and that of H3O+ and X- is cα
How did they figure out the equilibrium concentrations of the acid as c-cα?