Trends in properties of the halogensAQA A-Level Chemistry: Mind map

Exam questions on Trends in properties of the halogens

1. A student is comparing the halogens using data from a textbook. The Pauling electronegativity values given are fluorine 4.0, chlorine 3.0, bromine 2.8 and iodine 2.5.
   Hydrogen has a Pauling electronegativity of 2.2. State and explain which is the more polar bond, H–Cl or H–I.2 marks
2. Chlorine, bromine and iodine are a gas, a liquid and a solid respectively at room temperature. Their boiling points are approximately 239 K, 332 K and 457 K.
   Explain why the boiling point of iodine is higher than that of chlorine.2 marks
3. A student investigates displacement reactions of the halogens in aqueous solution. In each test she adds a few drops of a halogen water to 1 cm³ of an aqueous potassium halide, adds 1 cm³ of cyclohexane, shakes the tube and allows the layers to separate.
   Chlorine water is added to aqueous potassium bromide. State the colour of the cyclohexane layer, write an ionic equation for the reaction and identify the species that is oxidised.3 marks