When comparing the reducing power of different metals, it's important to note that a metal with stronger reducing power can replace a metal with weaker reducing power in a solution containing its salt. In this context, the metals can be arranged in increasing order of reducing power:
Cu < Fe < Zn < Al < Mg.
Consequently, we can conclude that magnesium (Mg) has the ability to displace aluminum (Al) from a solution of its salt. However, aluminum (Al) lacks the capability to displace magnesium (Mg) in a similar manner.
So, the sequence in which these metals can replace each other in the solutions of their respective salts is as follows:
Mg > Al > Zn > Fe > Cu
Standard electrode potential for \( \text{Sn}^{4+}/\text{Sn}^{2+} \) couple is +0.15 V and that for the \( \text{Cr}^{3+}/\text{Cr} \) couple is -0.74 V. The two couples in their standard states are connected to make a cell. The cell potential will be:
To calculate the cell potential (\( E^\circ_{\text{cell}} \)), we use the standard electrode potentials of the given redox couples.
Given data:
\( E^\circ_{\text{Sn}^{4+}/\text{Sn}^{2+}} = +0.15V \)
\( E^\circ_{\text{Cr}^{3+}/\text{Cr}} = -0.74V \)

An electrochemical cell is a device that is used to create electrical energy through the chemical reactions which are involved in it. The electrical energy supplied to electrochemical cells is used to smooth the chemical reactions. In the electrochemical cell, the involved devices have the ability to convert the chemical energy to electrical energy or vice-versa.