Reagent Concentration, moles per litre (M)
Sodium hydroxide – NaOH (aq) 0.500
Hydrochloric acid – HCl (aq) 0.500
Methyl orange – C14H14N3NaO3S (l)

Experiment 1 Experiment 2
Mass used of tablet 1.246 g 1.201 g
Concentration of hydrochloric acid (HCl) 0.50 mol dm-3
0.50 mol dm-3

Volume of HCl added to the flask 0.0400 dm3
0.0400 dm3

Number of moles of HCl added 0.2 moles 0.2 moles
Concentration of NaOH (sodium hydroxide) 0.50 mol dm-3
0.50 mol dm-3

Volume of NaOH added to the flask 0.0100 dm3
0.0100 dm3

Number of moles of HCl reacted with NaOH 0.005 moles 0.005 moles
Moles of HCl neutralised by antacid 0.0395 moles 0.0395 moles

Titration of sodium hydroxide (NaOH)

Experiment 1 Experiment 2
Final volume (ml) 40.00 40.00
Initial volume (ml) 0.80 30.5
Volume used (ml) 39.2 9.5

Calculations
You should include all calculations.
Make sure all steps are shown in your sample calculation.
Any formulas used should be shown and explained.
+ balanced equation

Analysis
In your discussion, you should address the following points:

Explain the chemistry behind the two reactions that have occurred giving any relevant equations.

What do your results mean in terms of the ‘real neutralising power’ of your antacid? You should refer to your own results.

Critique of the experimental design including sources of uncertainty. What are the sources of uncertainty present in the experiment and how can these be minimised in future experiments?