Question

For a galvanic cell, the following half reactions are given. Decide, which will remain as reduction reaction and which will be reversed to become an oxidation reaction. Give reason for your answer. (I) Cr³⁺ + 3e⁻ → Cr(s); E° = – 0·74 V (II) Fe²⁺ + 2e⁻ → Fe(s); E° = – 0·44 V

In a galvanic cell, chemical energy of a redox reaction is converted into electrical energy, whereas in an electrolytic cell the redox reaction occurs on passing electricity. The simplest galvanic cell is in which Zn rod is placed in a solution of ZnSO₄ and Cu rod is placed in a solution of CuSO₄. The two rods are connected by a metallic wire through a voltmeter. The two solutions are joined by a salt bridge. The difference between the two electrode potentials of the two electrodes is known as electromotive force (emf). In the process of electrolysis, the decomposition of a substance takes place by passing an electric current. One mole of electric charge when passed through a cell will discharge half a mole of a divalent metal ion such as Cu²⁺. This was first formulated by Faraday in the form of laws of electrolysis. Answer the following questions :

A salt prepared by displacement reaction is __________.