Chapter 10: halogens done Flashcards
Trend in electronegativity down the group
decreases
more shells and distance and shielding from the nucleus
causes less attraction
Trend in reducing ability going down the group
increases as they can lose electrons more easily
Reaction of NaCl with Concentrated sulphuric acid
Produces NaHSO4 and steamy fumes of HCl gas are seen
how does a sulphuric acid reaction show that Br is a better reducing agent than Cl
Because Br is strong enough to reduce Sulphuric acid to sulphur dioxide
Reaction of NaBr with concentrated sulphuric acid
Steamy fumes of HBr and Brown fumes of Br aswell as SO2 choking gas being formed.
HBr + H2SO4 ===== SO2 + H2O + Br2
Reaction of NaI with concentrated sulphuric acid
Steamy fumes of HI, Black iodine solid, Eggy smell from H2S, Yellow sulfur gas and colourless SO2.
Iodine better reduceer so can take S from +6 to -2 and since it passes through 0 some sulfur solid is formed.
What does fl look like
pale yellow gas
what does chlroine look like
Greenish gas
what does Br look like
orange brown liquid
what does iodine look like
black solid or brown solution
How can you test for halides with silver nitrate and ammonia
add nitric acid to remove impurities
add silver nitrate
Cl forms white precipitate that dissolves in dilute ammonia
Br forms cream precipitate that dissolves in conc ammonia
I forms yellow precipiate which is insoluble in conc ammonia
How does Cl react with alkalis
form NaCl, NaOCl(sodium chlorate) and H2O which is used as bleach and disinfectant
Wats a disproportionation reaction
a reaction where the oxidation of the same element is increased and decreased in the same reaction.
trend in bp down the group
gets higher
more electrons
therefore more vdw forces
how does chlorine react with water?
HClO(aq) + HCl(aq)
