Question

Electrolysis is used in the purification of metals. Name the

(i) anode (ii) cathode (iii) electrolyte, you would use to get pure copper from a piece of impured copper.

Answer 1

Electro-refining of copper

• The most important use of copper is in the form of wire for electric transmission. for this, copper must be absolutely pure because very small amounts of impurities can reduce its conductivity to a great extent.

(i) The Anode is an Impure block of copper

(ii) The cathode is a Thin sheet of pure copper.

(iii) The electrolyte is an aqueous copper sulfate solution acidified with dilute sulphuric acid

• When the current is passed through the electrolyte, the copper ions of the copper sulfate solution are attracted to the cathode where they gain electrons and are deposited on the pure copper strips. the impure copper loses electrons and passes into the solution as soluble copper ions.