ES - The halogens and atom economy Flashcards
What is formed when silver ions react with halide ions?
A precipitate.
How do you test for halides?
Add dilute nitric acid to the sample to remove ions which might interfere with the reaction.
Then add silver nitrate solution.
If a precipitate is formed then you know that a halide is present.
What is the colour of the precipitate when silver nitrate is added to a fluoride ion?
No precipitate as AgF is soluble.
What is the colour of the precipitate when silver nitrate is added to a chloride ion?
White.
What is the colour of the precipitate when silver nitrate is added to a bromide ion?
Cream.
What is the colour of the precipitate when silver nitrate is added to a Iodine ion?
Yellow.
What do you add to the silver nitrate and halide solution if it is hard to identify the colour?
Ammonia solution.
What will happen when ammonia solution is added to AgCl?
Precipitate dissolves in dilute ammonia solution to give a colourless solution.
What will happen when ammonia solution is added to AgBr?
Precipitate remains unchanged if dilute ammonia solution is added, but will dissolve in concentrated ammonia solution to give a colourless solution.
What will happen when ammonia solution is added to AgI?
Precipitate does not dissolve, even in concentrated ammonia solution.
Why is chlorine dangerous?
It is toxic and corrosive so must be kept away from skin and eyes.
It is also harmful if breathed in - irritates respiratory system.
Increases fire risk as it is an oxidising agent.
Why does chlorine increase fire risks?
Because it is an oxidising agent.
Why should chlorine be kept away from flammable materials?
It is an oxidising agent so can increase the fire risk.
How is chlorine stored?
As liquid under pressure in small cylinders.
How is chlorine useful?
It is used in water treatment as adding chlorine sterilises water making it safe to drink/swim in - so we don’t get nasty and potentially dangerous infections.
It kills disease-causing microorganisms such as bacteria.
Used to make bleach.
