From the given standard reduction potentials, arrange the metals in decreasing order of their reducing power.
(A) $E^0_{Zn^{2+}/Zn} = -0.76V$
(B) $E^0_{Mg^{2+}/Mg}= -2.37 V$
(C) $E^0_{Al^{3-}/Al} = -1.67 V$
(D) $E^0_{Ag^+/Ag}= +0.80 V$
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → (B), (C), (A), (D)
Reducing power of a metal is directly related to its tendency to lose electrons, i.e., to be oxidized.
- Metals with more negative standard reduction potential ($E^\circ$) are stronger reducing agents.
- Given $E^\circ$ values:
|
Metal |
$E^\circ$ (V) |
|
Zn |
–0.76 |
|
Mg |
–2.37 |
|
Al |
–1.67 |
|
Ag |
+0.80 |
Arrange in order of increasing $E^\circ$ (more negative → stronger reducing agent)
$\text{Mg (–2.37) > Al (–1.67) > Zn (–0.76) > Ag (+0.80)}$