(2) Acid-base indicators are themselves often weak acids or bases. An example is methyl orange. This is a weak acid with a pKof 3.47. In an aqueous solution of methyl orange an equilibrium between the acid form and its conjugated base establishes: Hin(aq) = In- (aq) + H*(aq) The protonated form of methyl orange, Hin, is responsible for a reddish colour, while the conjugated base, In, is yellow. The final colour of the solution depends on the relative concentrations of both forms: [In-y[HIn). (a) () A solution of methyl orange is prepared at 0.10 M in water. Calculate the concentration of the conjugated base and the ratio of concentrations of the basic and acidic form: [In /[Hin]. (2 marks) (ii) What is the pH of this solution? (1 mark) (ii) The pH of the solution can be fixed by using an appropriate buffer. Calculate the ratio of concentration of conjugated base to acid, [In)[Hin), when the 0.1 M methyl orange solution is made up in a series of buffers at pH = 2, 4, 6, 8, 10, and 12 instead of pure water. =