An experiment was carried out to find the value of n in hydrated calcium ethanedioate, CaC₂O₄ n H₂O. 2.01 g of the compound was dissolved in deionised water and made up to 250 cm³ solution in a volumetric flask. When 25.0 cm³ of this solution was acidified using an excess of dilute sulfuric acid, it was found to react with 27.50 cm³ of 0.0200 mol dm⁻³ potassium manganate(VII).
a. Explain why the conical flask had to be heated during this titration.
b. Explain why after a while the manganate(VII) ions did decolourise straight away.
c. Find the relative formula mass of hydrated calcium ethanedioate and the value of n.