Elements from the Sea - Halogens Flashcards
What is the state and colour of Fluorine at rtp?
pale yellow gas
What is the state and colour of Chlorine at rtp?
green gas
What is the state and colour of Bromine at rtp?
red liquid, orange/red gas
What is the state and colour of Iodine at rtp?
Grey solid, purple gas
Which halogen reacts with water?
Fluorine
What is the solubility of the halogens in water?
Cl, Br and I are not very soluble in water
F reacts with it - doesn’t dissolve at all
What type of substance are the halogens very soluble in?
Organic solvents eg cyclohexane
What colour is iodine when dissolved in water?
Brown/yellow
What is the trend of electronegativity in the halogens?
Electronegativity decreases as you go down the group
What is the trend of melting/boiling points in the halogens?
Higher mpt/bpt as you go down the group
Why does the melting/boiling point increase down the halogens?
They have more electrons, so in an instantaneous dipole the intermolecular attraction is stronger
Why do the halogens get less reactive down the group?
Distance between outer electron and nucleus is further
More energy needed to gain an extra electron
Lower electrostatic attraction / electronegativity
What colour is chlorine when dissolved in water?
pale green
What colour is bromine when dissolved in water?
orange/yellow
What colour is iodine when dissolved in cyclohexane?
violet
What colour is bromine when dissolved in cyclohexane?
orange/brown/red
What colour is chlorine when dissolved in cyclohexane?
pale green
How can the silver halides produced in the test for halogens be distinguished?
By adding ammonia solution:
Chlorine - colourless
Bromine - pale cloudy
Iodine - very cloudy
What happens when potassium chloride is reacted with concentrated sulphuric acid?
white liquid formed that bubbles and fizzes to produce a white smoke
What is produced when potassium chloride and sulphuric acid react?
HCl + KHSO4
What happens when potassium bromide reacts with sulphuric acid?
brown/orange liquid that evaporates into a white smoke
What is produced when KBr reacts with H2SO4 ?
SO2 + Br2 + H2O
What happens when potassium iodide reacts with sulphuric acid?
brown/grey liquid produced that fizzes and bubbles
What is produced when KI reacts with H2SO4?
hydrogen sulphide, iodine and water
Which halogen is the strongest oxidising agent?
Fluorine
Which halogen is the strongest reducing agent?
I-
What is produced when hydrogen halides react with sulfuric acid?
Fluoride and Chloride - don’t react
Bromide - produces sulfur dioxide
Iodide - produces hydrogen sulfide
What happens when the hydrogen halides react with ammonia?
a white cloud of ammonium halide is produced
Which hydrogen halides can be thermally decomposed?
hydrogen bromide
hydrogen iodide
