Certain cells are given below.1. In Daniel cell, if Zn electrode is re

1.	Certain cells are given below.1. In Daniel cell, if Zn electrode is replaced by Mg what happens? Why?2. Zinc displaces copper from copper sulphate solution while copper doesn’t replace zinc from zinc sulphate solution. Justify your answer.
Answer» 1. If Zinc electrode is replaced by Mg, a greater voltage (> 1.1 V) will be produced by the cell. Because Mg lies above Zn in electrochemical series. \(E^\circ\)_{(Mg²⁺Mg) =}-2.36 V \(E^\circ\)_{(Zn²⁺Zn) =}-0.76 V i. e., Mg is a stronger reducing agent than Zn. 2. Zinc lying above hydrogen in the electrochemical series has relatively greater tendency to lose electrons. Hence Zn is capable of displacing hydrogen from acids. Moreover, a more active metal Zn, displaces, a less reactive copper from the salt solution. But Cu, being less active than Zn cannot displace Zn from its salt, ZnSO₄.

Certain cells are given below.1. In Daniel cell, if Zn electrode is replaced by Mg what happens? Why?2. Zinc displaces copper from copper sulphate solution while copper doesn’t replace zinc from zinc sulphate solution. Justify your answer.

Answer»

1. If Zinc electrode is replaced by Mg, a greater voltage (> 1.1 V) will be produced by the cell. Because Mg lies above Zn in electrochemical series.

\(E^\circ\)_{(Mg²⁺Mg) =}-2.36 V

\(E^\circ\)_{(Zn²⁺Zn) =}-0.76 V

i. e., Mg is a stronger reducing agent than Zn.

2. Zinc lying above hydrogen in the electrochemical series has relatively greater tendency to lose electrons. Hence Zn is capable of displacing hydrogen from acids. Moreover, a more active metal Zn, displaces, a less reactive copper from the salt solution. But Cu, being less active than Zn cannot displace Zn from its salt, ZnSO₄.

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