Question

Given standard reduction potentials:
$C{o}^{3+}+e^{-}\to C{o}^{2+};E^o=+1.81V$
$P{b}^{4+}+2e^{-}\to P{b}^{2+};E^o=+1.67V$
$C{e}^{4+}+e^{-}\to C{e}^{3+};E^o=+1.61V$
$B{i}^{3+}+3e^{-}\to Bi;E^o=+0.20V$

oxidizing power of the species will increase in the order:

• A. $C{e}^{4+}<P{b}^{4+}<B{i}^{3+}<C{o}^{3+}$
• B. $B{i}^{3+}<C{e}^{4+}<P{b}^{4+}<C{o}^{3+}$
• C. $C{o}^{3+}<C{e}^{4+}<B{i}^{3+}<P{b}^{4+}$
• D. $C{o}^{3+}<P{b}^{4+}<C{e}^{4+}<B{i}^{3+}$

Answer 1

The correct option is B $B{i}^{3+}<C{e}^{4+}<P{b}^{4+}<C{o}^{3+}$

Lower the reduction potential, lower is the tendency of species to get reduced and hence less oxidizing power.
Standard reduction potential increases in the order:
$B{i}^{3+}<C{e}^4<P{b}^{4+}<C{o}^{3+}$
Hence the oxidizing power of the species will increase in the same order i.e.
$B{i}^{3+}<C{e}^4<P{b}^{4+}<C{o}^{3+}$