with paper chloride bromide iodide hydrocarbon solution solution solution solvent chlorine aqueous: pale turns red no change in very pale orange yellow-green to then quickly colour yellow solution colourless bleaches to solution formed cyclohexane: a pale brown formed colourless to pale bromine aqueous: turns yellow no change in no change in colour to no obvious colour colour darkens from – colourless bleaching cyclohexane: to colourless to brown pale Iodine aqueous: brown paper turns no change in no change in no change in to colourless green no colour colour colour – cyclohexane: obvious colourless to bleaching pink/purple Answer to questions 1. Compare the colour of the halogens in the cyclohexane with the colour of their vapours [2 marks] The vapour colours of the halogens are chlorine pale yellow/green, bromine – iodine pink/purple – The colour of the halogen solution in cyclohexane are similar to the halogen vapour colours 2. Using specific examples from your observations state and explain the trend in the reactivity of the halogens. Make specific reference to the outer shell electrons of the halogen atoms. [6 marks] The reactivity trend of the halogens is chlorine > bromine > iodine Chlorine displaces bromine and iodine from solution as shown by the dark solutions formed when chlorine water is mixed with potassium bromide and potassium iodide Bromine displaces iodine, but not chlorine, from solution as shown by the darker solution forming when bromine water is mixed with potassium iodide Chlorine is the most reactive of these three halogens as its outer electron shell is closest to
with hydrocarbon solvent paper chloride solution bromide solution iodide solution chlorine aqueous: pale yellow-green to colourless cyclohexane: colourless to pale turns red then quickly bleaches to a pale brown no change in colour very pale yellow solution formed orange solution formed bromine aqueous: to colourless cyclohexane: colourless to pale turns yellow – no obvious bleaching no change in colour no change in colour colour darkens from to brown Iodine aqueous: brown to colourless cyclohexane: colourless to pink/purple paper turns green – no obvious bleaching no change in colour no change in colour no change in colour Answer to questions 1. Compare the colour of the halogens in the cyclohexane with the colour of their vapours [2 marks] The vapour colours of the halogens are chlorine – pale yellow/green, bromine iodine – pink/purple The colour of the halogen solution in cyclohexane are similar to the halogen vapour colours 2. Using specific examples from your observations state and explain the trend in the reactivity of the halogens. Make specific reference to the outer shell electrons of the halogen atoms. [6 marks] The reactivity trend of the halogens is chlorine > bromine > iodine Chlorine displaces bromine and iodine from solution as shown by the dark solutions formed when chlorine water is mixed with potassium bromide and potassium iodide Bromine displaces iodine, but not chlorine, from solution as shown by the darker solution forming when bromine water is mixed with potassium iodide Chlorine is the most reactive of these three halogens as its outer electron shell is closest to
360166-pag-activity-chemistry-reactivity-trends-suggestion-1.docx