Question

Given the reduction potentials of
$ Na^{+}, Mg^{2+}, Al^{3+} $ and $ Ag^{+} $ as
$ E^{\circ}_{Na^{+} /Na} =-2.71\,V ; E^{\circ}_{Mg^{2+} / Mg}=-2.37\,V $
$ E^{\circ}_{Al^{3+}/Al}=-1.66V ; E^{\circ}_{Ag^{+}/ Ag}=0.08 \,V $
The least stable oxide is

• A. $ Ag_{2}O $
• B. $ Al_{2}O_{3} $
• C. $ MgO $
• D. $ Na_{2}O $

Answer 1

Answer: (A)

As the value of reduction potential of the metal ion increases, the tendency of metal oxide to get reduce into metal increases
Since, reduction potential of only $Ag$ is positive among the given, thus, $Ag_{2}O$ readily gets reduced into $Ag$ metal. In other words, it can be said that $Ag_{2}O$ is the least stable oxide among the given