Fig. 2.1 shows the burette readings for two of the titrations. Enter the burette readings into Table 2.1. Finish Table 2.1.
Put a tick ($\checkmark$) against the two best titration results in Table 2.1.
Use the ticked ($\checkmark$) titration results in Table 2.1 to work out the mean volume of aqueous ethanedioic acid needed to neutralise $25.0\,\text{cm}^3$ of the aqueous sodium hydroxide.
Calculate the amount of substance, in moles, of $\text{NaOH}$ present in $25.0\,\text{cm}^3$ of $0.800\,\text{mol dm}^{-3}$ $\text{NaOH(aq)}$.
Two moles of sodium hydroxide are neutralised by one mole of ethanedioic acid. Use your answers to (c) and (d) to find the concentration, in $\text{mol dm}^{-3}$, of ethanedioic acid. Give your answer to three significant figures.
The formula of ethanedioic acid is $\text{C}_2\text{H}_2\text{O}_4\cdot n\text{H}_2\text{O}$. $100\,\text{cm}^3$ of the aqueous ethanedioic acid contains $6.3\,\text{g}$ of $\text{C}_2\text{H}_2\text{O}_4\cdot n\text{H}_2\text{O}$. Use your answer from (e) to determine the relative formula mass, $M_r$, of $\text{C}_2\text{H}_2\text{O}_4\cdot n\text{H}_2\text{O}$.
Use your answer from (f)(i) to find the value of $n$ in $\text{C}_2\text{H}_2\text{O}_4\cdot n\text{H}_2\text{O}$. Give your answer to the nearest whole number. $[A_r: \text{H} = 1, \text{C} = 12, \text{O} = 16]$
State why a white tile is put under the conical flask before aqueous ethanedioic acid is delivered from the burette.
State why a measuring cylinder is not used to measure $25.0\,\text{cm}^3$ of $\text{NaOH(aq)}$ in this experiment.