Electrolysis of brine PPT, from my chemistry teacher. Mr.Bedford. For anyone who can use this for help. This is for IGCSE /GCSE Level.

1. Chemicals from Salt

2. Common and Chemical Names
Name of substance Chemical composition
Rock salt Mineral containing mainly
sodium chloride mixed
with a red clay.
Salt Sodium chloride, NaCl
Brine Aqueous solution of
sodium chloride.
Caustic soda Sodium hydroxide,
NaOH

3. Solid Salt
1. Used as a preservative for foods
2. Used to treat and preserve animal skins.
3. Added to foods for flavouring.
4. Used to treat ice on roads in the winter.
5. The raw material for the manufacture of
many other important chemicals.

4. Extraction of Rock Salt
In countries like Britain there are large
underground deposits of rock salt.
The rock salt is mined as a solid and
brought to the surface as a powdered
rock.

5. Extraction of brine
The rock salt can be dissolved when
water is pumped down onto the solid
mineral. A solution containing dissolved
salt is pumped back to the surface.

7. Electrolysis of the Brine
1. The brine is purified.
2. The solution is passed into an
electrolytic cell containing a
diaphragm.
3. A continuous process converts the
brine(sodium chloride) into three
useful products.

9. Answers
In the diaphragm process the gaseous
products are separated from each
other. Explain
The hydrogen and chlorine react
together and can form an explosive
mixture.

10. Answers
The anode product is separated fro
mthe solution drawn off at S and Q.
Explain
The chlorine reacts with the sodium
hydroxide to form a mixture of
products.

11. The Ions that are
Discharged
In the initial solution there are ions
from both the water and the sodium
chloride.
NaCl(aq) Na→ +
(aq) + Cl-
(aq)
H2O(l) H→ +
(aq) + OH-
(aq)

12. Ion Discharged at the
Anode
Only one ion is discharged from the
anode. There are two negative ions in
the solution, Cl-
and OH-
. The ion from
the element lowest in the Reactivity
Series is the one discharged.
2Cl-
(aq) - 2e-
Cl→ 2(g)

13. Ion Discharged at the
Cathode
Only one ion is discharged from the
cathode. There are two positive ions in
the solution, Na+
and H+
. The ion from
the element lowest in the Reactivity
Series is the one discharged.
2H+
(aq) + 2e-
H→ 2(g)

14. Ions Left in Solution
The sodium ion and hydroxide ion are
not discharged. This leaves a solution
of sodium hydroxide.

15. Products from Electrolysis
1. Sodium hydroxide.
2. Hydrogen.
3. Chlorine.

16. Answers
In what state are the chlorine and
hydrogen transported fro mthe
electrolysis plant?
Hygrogen – Gas
Chlorine – Liquid

17. Answers
Chlorine is used in the manufacture of
chlorinated solvents (30 %), monomers
for plastics (25 %) and bleaching
agents (15 %).
(i)Name TWO chlorinated solvents and
state ONE use for the solvents.

18. Uses of Chlorine

19. Uses of Sodium Hydroxide

20. Uses of Hydrogen