Paper 2 · Titration apparatus, indicators and obtaining pure crystals
In a titration where sodium hydroxide solution, NaOH(aq), is added from a burette into a conical flask containing dilute sulfuric acid, H2SO4(aq), with 2-3 drops of a solution Y added to the acid beforehand, what is the role of solution Y?
AIt is an indicator that changes colour to show the end point of the reaction.
BIt is a catalyst that increases the rate of the neutralisation reaction.
CIt is a buffer that keeps the pH of the mixture constant throughout the titration.
DIt is the limiting reagent that determines the maximum yield of salt formed.
Explanation: Solution Y is an indicator: it changes colour according to pH, showing when the acid has been exactly neutralised (the end point).
Derived from ZIMSEC Chemistry 4024/2 Paper 2 Theory, November 2019, Q1
