Ch8 - Chlorine alkali industry Flashcards
(21 cards)
Describe Cl
very reactive
can’t exist by itself
What are the raw materials
NaCl and KCl
Where are the raw materials extracted from
Salt mine + sea water
What are Cl applications
PVC
Solvents
Water treatments
Amount of Cl produced 10 years ago
10 tonnes
NaCl is a byproduct, what are its application
soaps
bleach
water treatment
food
phosphates
What is the main production process
electrolysis
what is electrolysis
passing an electric current through a solution of brine (NaCl dissolved in water)
3 types of production process
- Hg-based
- Membrane
- Diaphragm
What is the name of the spontaneous process
galvanic cell
which process is used out of the 3
membrane
What describes a galvanic cell?
delta G <0, delta U°>0
normal redox in terms of voltages
What is the name of the non-spontaneous process
electrolysis
What are the differences between electrolysis and a galvanic cell
delta G >0, delat U° <0
Forced process
In whihc process do we use a salt bridge
spontaneous
What is the solution to proceed to an electrolysis
Add a membrane and Brine solution (NaCl (aq))
What is special with the membrane
its a semi-permeable membrane
Explain semi-permeable membrane
blocks migration of OH- to anode
permeable for Na+ (Cation seelctive)
restores elctro-neutrality
What are the 2 inlets/outlets of brine solution/membrane electrolysis
- NaCl –> NaOH
- H2O –> Depleted Brime
Describe the mercury cell process
At the cathode: formation of Na/Hg amalgam
Hg has to be recovered = regenerator with catalyst
2 cells
–>
1.decomposition of amalgam
2. graphite packing with transition metal (Fe or Ni) to catalyse amalgam decomposition
3. Recycle of Hg
Direct prod of NaOH
Why is Hg-process stopped
mercury poisoning
