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+ –
ELECTROLYSIS Positively-charged ions
The process of breaking up of an electrolyte are called cations while Anode Cathode
chemically on passing an electric current negatively-charged + –
through it is called electrolysis. particles are called
anions.
A substance which conducts electricity in the
liquid state or when dissolved in water and When electric current is –
breaks up chemically during the process is passed through the – +
called an electrolyte. Let us demonstrate the solution, the cations – +
process through an experiment. move towards the +
negatively-charged
Experiment : To demonstrate chemical effect
of electric current on water. electrode (cathode) and Movement of ions during
electrolysis
Take two iron nails. Clean them with sand anions towards the positively-charged
paper. Wrap one or two rounds of copper wire electrode (anode).
around them and connect the other ends of Electrolysis finds its use in various commerical
the wires to the two terminals of battery. Take applications, such as :
water in a beaker and add to it a little salt or a ! Refining and extraction of metals
few drops of sulphuric acid to make it ! Electroplating, etc.
conducting. Immerse the nails (called
electrodes) in the solution. Observe the nails Dry cell : A dry cell converts chemical energy to
carefully. Can you see small bubble of gases electrical energy. Each dry cell can produce a
voltage of 1.5V.
coming out from the water near the nails?
Chemical energy can be converted to
+ –
electricity. But the reverse is also true. Passage
of electric current can also allow or can assist in
chemical reaction to occur.
Water +
Sulphuric acid
Passing electric current through water
It can be checked that the gases evolved are
hydrogen and oxygen.
When an electrolyte such as copper sulphate is
dissolved in water, it breaks up into positively
and negatively-charged particles called ions.
A generator is a device that converts mechanical energy to electrical energy. The process is based on the relationship
between magnetism and electricity.
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