Chemistry 9701/31 May June 2018 | Cambridge AS Level Past Papers With Mark Scheme

1. Titration of Sodium Carbonate with Hydrochloric Acid:
- This experiment involves determining the concentration of hydrochloric acid (HCl) by titrating it with a known solution of sodium carbonate (Na₂CO₃).
- The procedure requires you to use methyl orange as an indicator and perform multiple titrations to obtain consistent results.
- You will calculate the number of moles of sodium carbonate and HCl involved, and then use these results to find the concentration of the HCl solution.

2. Determining the Identity of a Halogen in Halogenoethanoic Acid:
- In this experiment, you're tasked with determining the halogen (X) in CH₂XCO₂H by titrating the remaining sodium hydroxide (NaOH) solution (FA 3) after reacting with the halogenoethanoic acid.
- After titrating with hydrochloric acid (FA 4), you calculate the amount of sodium hydroxide that reacted, then determine the identity of the halogen by using the Mr of the compound.