Halide reactions and predicting halogen chemistryEdexcel International A Level Chemistry: Mind map

Exam questions on Halide reactions and predicting halogen chemistry

1. A technician tests three unlabelled solid sodium halides, each known to be sodium chloride, sodium bromide or sodium iodide. In a fume cupboard she adds a few drops of concentrated sulfuric acid to a small sample of each and records what happens.
   Explain why iodide ions reduce concentrated sulfuric acid but chloride ions do not.2 marks
2. A student adds aqueous silver nitrate, acidified with dilute nitric acid, to separate aqueous solutions of potassium chloride, potassium bromide and potassium iodide. She then tests how each precipitate behaves with aqueous ammonia.
   Explain why dilute nitric acid is added to the halide solution before the silver nitrate.2 marks
3. Hydrogen chloride gas is made in the laboratory by warming solid sodium chloride with excess concentrated sulfuric acid. In one experiment the gas is passed into a gas jar of ammonia gas. In another it is bubbled into water. Take the molar volume of a gas at room temperature and pressure as 24 dm³ mol⁻¹.
   State what is seen when hydrogen chloride gas meets ammonia gas, write the equation for the reaction and state the role of the ammonia.3 marks