Sodium chloride (salt) Flashcards
how can sodium chloride be obtained?
from the sea or from salt deposits
what does the electrolysis of concentrated sodium
chloride give?
chlorine and hydrogen
what is the chemical test for chlorine?
it bleaches moist litmus paper
what is sodium chloride used as?
- as a preservative
* as a flavouring
where is sodium chloride important?
it is an important raw material in the chemical industry, including use as a source of chlorine and sodium hydroxide
what are household bleach, PVC and solvents are
made from?
substances derived from salt.
what is chlorine used for?
to sterilise water and to make solvents, household bleach and plastics
what is hydrogen used in?
the manufacture of margarine
what is sodium hydroxide used to make?
soap
Explain how mining for salt can lead to subsidence
taking salt out leaves a hole underground, rock can collapse into hole, buildings collapse
Recall the products of the electrolysis of concentrated
sodium chloride solution (brine)
- hydrogen made at the cathode
- chlorine made at the anode
- sodium hydroxide is also made
Explain how the electrolysis of sodium chloride
solution (brine) produces sodium hydroxide, hydrogen
and chlorine:
- NaCl(aq) contains Na+, OH−, Cl−, H+
- cathode 2H+ + 2e− → H2
- anode 2Cl− – 2e− → Cl2
- ions not discharged make sodium hydroxide.
Explain the economic importance of the chlor-alkali
industry
industry based on the electrolysis of brine, very important and worth billions of pounds a year
Describe how sodium hydroxide and chlorine are
used to make household bleach.
by reacting sodium hydroxide and chlorine together
Explain why it is important to use inert electrodes in
the electrolysis of sodium chloride solution
so that they don’t react with hydrogen, chlorine or sodium hydroxide
