Group 7 halogens Flashcards
What colour is fluorine at room temperature?
Pale yellow gas
What colour is chlorine at room temperature?
Greenish gas
What colour is bromine at room temperature?
Red-brown liquid
What colour is iodine at room temperature?
Black solid
The F-F bond is…
Weak
Melting and boiling points increase…
Going down a group because of the increase in electrons
Oxidising power increases going…
Up the group
React with metal halides in…
Displacement reactions
Reducing power increases going…
Down the group
Observation and equation for concentrated sulfuric acid and solid sodium chloride.
NaCl (s) + H2SO4 → NaHSO4 (s) + HCl (g)
Steamy fumes of hydrogen chloride
similar reaction occurs with NaF but releases steamy fumes of HF
Observation and equations for the reaction between sodium bromide and concentrated sulfuric acid.
Steamy fumes of hydrogen bromide
Brown fumes of bromine
NaBr (s) + H2SO4 → NaHSO4 (s) + HBr (g)
2H+ + 2Br- + H2SO4 (l) → SO2 (g) + 2H20 (l) + Br2 (l)
Observation and equations for the reaction between sodium iodide and concentrated sulfuric acid.
Steamy fumes of hydrogen iodide
Black solid of iodine
Egg smell of hydrogen sulfide gas
Yellow solid sulfur may be seen
NaI (s) + H2SO4 (l) → NaHSO4(s) + HI (g)
8H+ + 8I- + H2SO4 → H2S (g) + 4H20 (l) + 4I2(s)
How do you identify metal halide?
Add dilute nitric acid to get rid of any soluble CO32- or OH- to prevent the formation of insoluble AgOH/CO3
This forms H20 CO2 and NO3-
Add a few drops of silver nitrate
Precipitate forms
What colour is the silver fluoride in the metal halide test?
No precipitate because silver fluoride is soluble
What colour is silver chloride precipitate in the metal halide test?
White precipitate
Dissolves in dilute ammonia
