ES 5 The risks and benefits of using chlorine

What are some negative uses of chlorine?

• pesticides with organochlorine compounds

• CFCs

• poisonous gas

What is chlorine transported in?

pressurised tank containers

In what state is chlorine transported and why?

liquid

more can be stored

What happens if temperature or pressure becomes too high in the tank?

pressure release devices release some chlorine as gas

Why is the inside of the tank dry?

chlorine reacts with water to make corrosive acids

What are the tanks made and lined with?

steel

How is all loading and unloading done?

protective housing at the top

When is the excess flow valve closed automatically?

if angle valve which regulates discharge is broken or sheared off

What does the scrubber unit ensure when chlorine is transferred from the rail tanker to a bulk tanker?

air being displaced from the bulk trailer has any chlorine removed from it

What does the scrubber unit contain?

sodium hydroxide

What does the reaction of sodium hydroxide and chlorine produce?

sodium chlorate(I)

What is chlorine stored in?

cylinders

What is used to move the chlorine cylinders to avoid damage?

hoist

What is one method of routine checking stored cylinder?

a white cloud of ammonium chloride will be seen if the cylinder is leaking when a stick with cloth soaked in concentrated ammonia solution is held

Why is chlorine used in water treatment?

kills bacteria and pathogens

Why is chlorine used as bleach?

it is an oxidising agent so breaks bonds in coloured compounds to form colourless compounds

What kind of reaction does iodine-thiosulfate titration involve?

REDOX

What are iodine thiosulfate titrations used to find?

concentration of a chemical that is strong enough oxidising agent