How weak is a weak acid?The IB does not require students to be able to solve quadratic equations when it comes to acids and bases calculations. This means that they are required to make an assumption that the equilibrium concentration of a weak acid in solution is the same as the concentration of the undissociated acid. How valid is this assumption?Consider a 0.100 mol dm-3 aqueous solution of ethanoic acid (Ka = 1.8...