This is for people doing industrial chem- I won't post any more optional questions because not everyone can do them obviously but this one is fantastic and deserves to posted:
The ionisation of acetic acid can be written as CH3COOH -> <- CH3COO (-) + H (+). The equilibrium constant for this reaction is 1.8x10^-5. A 0.5mol/L solution of acetic acid is made up. Calculate the pH of the resultant solution at equilbrium.