Image

Sunday, August 4, 2013

Electrolytic reduction of highly electropositive metals like Na, K, Mg, Ca, Al, (10th class)


The oxides of the highly electropositive metals like Na, K, Mg, Ca, Al, etc., cannot be reduced easily with carbon at moderate temperatures. For reduction, a very high temperature is required at which the metal may combine with carbon to form a carbide. These metals are thus extracted by the electrolysis of their oxides, hydroxides or chlorides in fused state. Sometimes, a small amount of some other salt is added as to lower the fusion temperature or to increase the conductivity or both. The metal is liberated at the cathode. Sodium is obtained by the electrolysis of fused mixture of NaCl and CaCl2 (Down's process) or by electrolysis of fused sodium hydroxide (Castner's process).

Extraction of Na from NaCl

At cathode    Na+ + e-  --->Na
At anode    2Cl-  ---> Cl2 + 2e-

Chemistry X Metals and Non-metals MCQ Solved exam questions Term-1
Chemistry X Metals and Non-metals Solved exam questions Term-1
10th Metal and non metal (2 marks questions ) By Jsunils
X Metals and Non-Metals Solved Important Guess Questions
Chemistry X- COMMON ORES OF ALUMINIUM, IRON AND ZINCCBSE Guess Paper SCIENCE Class-10 Chapter 3. Metal and Non-metals
CBSE TEST PAPER SCIENCE Class-10 Chapter 3. Metal and Non-metals



No comments:

Post a Comment

Related Posts Plugin for WordPress, Blogger...