Write about the terms that are commenly used in Describing chemical effect of current.
Answers
Terms commenly used in Describing chemical effect of current are :
1. Ions
When an atom loses or gains electron (s), it forms ion (s). Electrically charged atoms or group of atoms are called ions. There are two types of ions - cations and anions.
(a) Cations :When an atom loses electron (s), it becomes positively - charged ion. Positively- charged ions are called cations.
(b) Anions :When an atom gains electron (s), it becomes negatively - charged ion. Negatively - charged ions are called anions.
2. Electrolytes
Chemical compounds whose molecules ionise (separate) into positively and negatively charged ions in a solution are called electrolytes. So, electrolytes are chemical compounds which conduct electricity when dissolved in water (or in molten state). An electrolyte produces ions, when it dissolves in water. For example, when sodium chloride (common salt) is dissolved in water, it produces sodium ions (cations) and chloride ions (anions). The solution of sodium chloride in water is called aqueous solution of common salt.
3. Non-electrolytes
Some compounds such as glucose and alcohol dissolve in water but do not form ions. All such solutions that do not form ions, do not conduct electricity. Such compounds are called non - electrolytes. Non - electrolytes are chemical - compounds which do not conduct electricity when dissolved in water.
4. Electrolysis
When electric current is passed through an aqueous solution of common salt (sodium chloride), it decomposes(breaks) the chemical compound sodium chloride into sodium ions (cations) and chloride ions (anions). This process is called electrolysis. The decomposition of an electrolyte, when electric current is passed through it is called electrolysis.
5. Electrodes
The metal rods or plates through which the current enters or leaves the electrolyte are called electrodes. They are of two kinds :
(a) Cathode : The electrode connected to the negative terminal of a cell/battery is called cathode. During electrolysis, the positively- charged ions (cations) present in the electrolyte move towards it.
(b) Anode : The electrode connected to the positive terminal of a cell or battery is called anode. During electrolysis, the negatively - charged ions (anions)present in the electrolyte move towards the anode.
6. Voltameter (Electrolytic Cell)
A glass or plastic container containing two electrodes and the electrolyte is called voltameter. The voltameter convert electrical energy into chemical energy. In voltameter, the process of electrolysis is carried out.