Solution X contains a mixture of a dibasic acid, ethanedioic acid H2C2O4, and a salt, sodium ethanedioate Na2C2O4. A student performed two titrations to determine the concentrations of ethanedioic acid and sodium ethanedioate in solution X.
In the first titration, 25.0 cm3 of solution X required 14.75 cm3 of 0.1 mol/dm3 sodium hydroxide solution for neutralisation.
In the second titration, 25.0 cm3 of solution X required 32 cm3 of 0.0205 mol/dm3 potassium manganate (VII) solution for complete oxidation. In the oxidation reaction, all the (bivalent ethanedioate) C2O4 ions are oxidised to CO2 in acidic conditions.
(a) Write the equation for the reaction between ethanedioic acid H2C2O4 abd sodium hydroxide solution to form sodium ethanedioate Na2C2O4 and water. Use this equation and the results if the first titration to calculate tge concentration of ethanedioic acid in solution X.
(b) (i) Construct a balanced ionic equation for the reaction between (bivalent ethanedioate) ions C2O4 and (univalent) manganese (VII) ions MnO4-.
(b) (ii) Using the balanced equation in (b)(i) abd the result of the second titration, calculate the total amount of (bivalent ethanedioate) C2O4 ions present in 25 cm3 of solution X.
(c) Hence, calculate the concentration of sodium ethanedioate in solution X.