Titration problem 2

0.39 g of hydrated sodium carbonate were weighed out on a balance reading to the nearest 0.01 g. This was then dissolved in water and made up to 250 cm³ in a volumetric flask. 25 cm³ portions of this solution were titrated with 0.0100 M hydrochloric acid using methyl orange indicator. The titres were 29.40, 29.35 and 29.30 cm³. Calculate the number of moles of water of crystallization present per mole of sodium carbonate.

The actual formula on the bottle is given as Na₂CO₃.10H₂O. Evaluate the accuracy and reliability of this experiment (this means error analysis - if you haven't seen this section yet, check it out first).

The equation for the reaction is:

Na₂CO₃(aq) + 2HCl(aq) ⇒ 2NaCl(aq) + H₂O(l) + CO₂(g)

Answer