Enter the burette readings in Table 2.1 and then finish Table 2.1.
Tick (✓) the two most reliable titration results in Table 2.1.
Use the ticked (✓) titration results in Table 2.1 to work out the mean volume of $\text{HCl(aq)}$ required to neutralise $25.0\,\text{cm}^3$ of the aqueous sodium carbonate.
Use your result from (c) to work out the number of moles of $\text{HCl}$ in the average volume of $\text{HCl(aq)}$ needed to neutralise $25.0\,\text{cm}^3$ of the aqueous sodium carbonate.
The equation for the reaction between hydrochloric acid and sodium carbonate is $\text{2HCl} + \text{Na}_2\text{CO}_3 \rightarrow \text{2NaCl} + \text{H}_2\text{O} + \text{CO}_2$. Use your result from (d) to find the concentration of the aqueous sodium carbonate. Give your answer to three significant figures.
The student is given $150\,\text{cm}^3$ of the aqueous sodium carbonate. Use your answer to (e) to find the mass of $\text{Na}_2\text{CO}_3$ in $150\,\text{cm}^3$ of this solution. [$A_r$: C, 12; O, 16; Na, 23]
State why the conical flask is swirled while $\text{HCl(aq)}$ is added from the burette.
State why the $\text{HCl(aq)}$ is added drop by drop near the end-point.