Review A-Level Edexcel Chemistry halide tests and reducing ability through sulfuric acid reactions, silver nitrate precipitates and ammonia solubility.
This question is about trends in the Periodic Table.
Compare and contrast the reactions of concentrated sulfuric acid with solid sodium chloride and with solid sodium bromide.
An answer that makes reference to four of the following points:
Any two from:
(Similarities)
- both produce hydrogen halides
- formation of hydrogen halides is protonation
(1)
- both give off misty/steamy/white fumes
(1)
Any two from:
(Differences)
- only the reaction of sodium bromide is redox / bromide ions are stronger reducing agents (than chloride ions)
(1)
- (red-) brown fumes / gas / liquid produced with sodium bromide
(1)
- sulfur dioxide (colourless choking gas) / bromine given off with sodium bromide
(1)
Both similarities and differences can be shown in equations or with observations
Accept NaX+H_2 SO_4 HX+NaHSO_4
Allow 2 NaX+H_2 SO_4 2 HX+Na_2 SO_4
Do not award white smoke
Do not award rotten egg smell / references to yellow solid
Accept 2 HBr+H_2 SO_4 Br_2+SO_2+2 H_2 O
Apply list principle
(4)