1. Conductors of Electricity →
Substances through which electricity can pass are called Conductors of Electricity..
Example :: Copper, Gold, Silver etc.
2.Non-conductors of electricity or Insulators →
Substances through which electricity cannot pass are called Non-conductors of
electricity or Insulators.
Example :: Dry wood , Glass, Glucose etc.
3. Metallic conductors of electricity →
Metals through which electricity can pass without producing any chemical change in them
are called Metallic conductors of electricity .
Example :: Silver , Gold , Mercury etc.
4. Non-metallic conductors of electricity →
Non-metals through which electricity can pass without producing any chemical change in
them are called Non-metallic conductors of electricity.
Example :: Graphite, Gas Carbon.
The substances which conduct electricity in aqueous solution or in molten state but cannot conduct electricity in solid state are called Electrolytes. During conduction of electricity ,these Electrolytes are decomposed chemically to give a new substance. Example :: Sulphuric acid (H2SO4), Hydrochloric acid (HCL) ,etc.
The substances which do not conduct electricity either in the molten state or in aqueous solution are called Non-electrolytes.
Example :: Sugar, Benzene etc.
The process of chemical decomposition of electrolytes in the aqueous solution or fused state when electric current is passed through them is called ‘Electrolysis’.It is a process where electrical energy is converted into chemical energy.
8. Voltameter →
The vessel in which electrolysis of electrolytes takes place either in fused state or in aqueous solution state is called Voltameter .
9. Weak electrolytes → Compounds which in the fused state or in suitable solvent dissociate partially to produce less number of ions and thus , allow small amounts of electricity to flow through them are called Weak electrolytes.
Example :: Acetic acid ( CH3COOH) , Ammonium hydroxide(NH4OH), etc.
10. Strong electrolytes →
Compounds which in the fused state or in suitable solvent , dissociate almost completely to produce large number of ions and thus, allow a large amount of electricity to flow through them are called Strong electrolytes.
Example :: Hydrochloric acid(HCL) , Sodium Chloride (NaCl), Sodium Hydroxide (NaOH),etc.
11.Electro plating →
The process of coating a thin layer of superior metal on the base metal by the process of electrolysis is called Electro-plating.
12. Purposes of electroplating →
i) To protect the article from rust .
ii) To make the article more beautiful.
13. Electrochemical Series →
The series in which the metallic elements are arranged in order of their decreasing tendency to lose electrons ( taking hydrogen as standard whose tendency to lose electron is taken to be zero) is called Electrochemical series.
Example :: Lithium(Li) has the highest tendency to lose electron, so its placed at the top of the series and gold (Au) has the lowest tendency to lose electron , so Au is placed at the bottom of the series.
1. Why some drops of acid added during electrolysis of water?
Ans: Pure water is a bad conductor of electricity , when some drops of acid added to it water becomes a good conductor of electricity ,that is why some drops of acid added during electrolysis of water.
2. What is used as anode, cathode and electrolyte when iron spoon is electroplated by silver ?
Ans: When iron spoon is electrified by silver, iron spoon is placed at cathode, pure silver is placed at anode and potassium argentocyanide K[Ag(CN)2] is used as electrolyte.
3. Can mercury conduct electricity?
Ans: Yes , mercury(Hg) can conduct electricity.
4. Is mercury an electrolyte?
Ans: No, mercury is not an electrolyte.
5. Name a liquid metal through which electricity can pass?
6. Name non-metal through which electricity can pass?
7. During electrolysis of water ,copper sulphate , sodium chloride, aluminium chloride, sulphuric acid, sodium hydroxide and HCl which decomposed in anode and cathode?
Electrolyte Anode Cathode
H2O O H2
CuSo4 So4 Cu
NaCl Cl Na
AlCl3 Cl3 Al
H2SO4 So4 H2
NaOH OH Na
HCl Cl H
8. Name the electrodes and electrolytes which are used for electroplating of an article with the following:- i) Copper, ii) Silver iii) Tin iv) Nickel v) Chromium vi) Gold