Question

Arrange the following metals in which they displace each other from the solutions of their salts in decreasing order. $Al$, $Cu$, $Fe$, $Mg$ and $Zn$.
$[E_{A{I}^{3+}/AI}^{\circ }=-1-66V$, $E^{\circ }C{u}^{2+}/Cu=+0.34V$
$E_{F{e}^{2+}/Fe}^{\circ }=-0.44V$, $E_{M{g}^{2+}/Mg}^{\circ }=-2.36V$ and
$E_{Z{n}^{2+}/Zn}^{\circ }=-0.76V]$

• A. Cu, Fe, Zn, Al, Mg
• B. Fe, Zn, Cu, Al, Mg
• C. Mg, Cu, Fe, Zn, Al
• D. Mg, Al, Zn, Fe, Cu

Answer 1

Answer: (D)

Since a metal with lower electrode potential is a stronger reducing agent. $Mg$ can displace all the given metals, Al can displace all metals except $Mg$. $Zn$ can displace all metals except $Mg$ and $Al$. $Fe$ can displace only $Cu$. The order in which they can displace each other from their salt solutions is $Mg$, $Al$, $Zn$, $Fe$, $Cu$.