ES Flashcards
(18 cards)
F₂ appearance
Pale yellow gas
Cl₂ appearance
Green gas
Br₂ appearance
Dark red liquid
I₂ appearance
Shiny grey solid - sublimes with purple vapour
Down halogens, BP and MP
increases (more electrons so strong i.d i.d)
Are halogens more soluble in water or organic solvents
Organic solvents
How is bromine produced
Add chlorine to sea water - to displace bromine from the bromide ions dissolved. Bromine is volatile and bromine vapour is given off. This is condensed and bromine and water form 2 layers, as bromine is not very soluble. The dense bromine layer is run off from the water layer that floats on top.
How to make a hydrogen halide
Add Sodium halide to sulfuric acid - forms sodium hydrogen sulfate and hydrogen halide
NaCl + H₂SO₄ forms
NaHSO₄ + HCl
NaBr + H₂SO₄ forms
NaHSO₄ + HBr
When HBr is formed from the reaction between NaBr and hydrogen sulphate, what happens next
The bromide ions produced (HBr -> H+ and Br- in solution) are strong enough reducing agents that they reduce unreacted H₂SO₄ to SO₂ + H₂O
What is the reaction for the second reaction of HBr with H₂SO₄ (from bromide ions and hydrogen ions)
2H⁺ + 2Br⁻ + H₂SO₄ → SO₂ + Br₂ + 2H₂O
NaI + H₂SO₄ forms
NaHSO₄ + HI
When HI is formed from the reaction between NaI and hydrogen sulphate, what happens next
The iodide ions produced (HI -> H+ and I- in solution) are such strong enough reducing agents that they reduce unreacted H₂SO₄ to H₂S + H₂O
What is the reaction for the second reaction of HI with H₂SO₄ (from iodide ions and hydrogen ions)
8H⁺ + 8I⁻ + H₂SO₄ → H₂S + 4I₂ + 4H₂O
Thermal stability of hydrogen halides
decreases down the group (less EN, so the bond strength decreases)
What happens when a hydrogen halide thermally decomposes
It forms Hydrogen gas and a halogen
Phosphoric acid + sodium halide
Hydrogen halide produced
