Question

In electro chemical reaction of which set of reactants, the metal displacement will not take place

• A. $Mg + Cu^{2+}$
• B. $Pb + Ag^{+}$
• C. $Zn + Cu^{2+}$
• D. $Cu + Mg^{2+}$

Answer 1

Answer: (D)

In electrochemical reaction of $Cu + Mg^{2+}$, the metal displacement will not take place.

Displacement reactions occurs when a metal from the electrochemical series is mixed with the ions of metal lower down in the series. In the electrochemical series $Mg$ is placed above $Cu$. Hence, metal displacement reaction won’t occur in $Cu + Mg^{2+}$. In $Pb + Ag^+$ and $Zn + Cu^{2+}$, lead and zinc are more reactive than silver and copper, hence they can displace silver and copper respectively from their salt solution