Question

which metal cation is the best oxidizing agent?

• A. ${\mathrm{Pb}}^{2+}$
• B. ${\mathrm{Cr}}^{3+}$
• C. ${\mathrm{Fe}}^{2+}$
• D. ${\mathrm{Sn}}^{2+}$

Answer 1

The correct option is A

${\mathrm{Pb}}^{2+}$

The explanation for the correct answer

(A)${\mathrm{Pb}}^{2+}$

1. ${\mathrm{Pb}}^{2+}$ is the best oxidizing agent as it has a very high reduction potential.
2. Reduction potential is defined as the ability of an electrode to gain electrons or to get reduced.
3. The reduction potential of ${\mathrm{Pb}}^{2+}$ is -0.13V. ${\mathrm{Pb}}^{2+}\left(\mathrm{aq}\right)+2{\mathrm{e}}^{-}\to \mathrm{Pb}\left(\mathrm{s}\right)$
4. Thus is the best oxidizing agent.

The explanation for the incorrect answers

(B)${\mathrm{Cr}}^{3+}$

1. ${\mathrm{Cr}}^{3+}$has the reduction potential -0.74V which is very less. ${\mathrm{Cr}}^{3+}\left(\mathrm{aq}\right)+2{\mathrm{e}}^{-}\to \mathrm{Cr}\left(\mathrm{s}\right)$
2. So, is not a good oxidizing agent.

(C)${\mathrm{Fe}}^{2+}$

1. ${\mathrm{Fe}}^{2+}$ has the reduction potential -0.44V. ${\mathrm{Fe}}^{2+}\left(\mathrm{aq}\right)+2{\mathrm{e}}^{-}\to \mathrm{Fe}\left(\mathrm{s}\right)$
2. So, not a good oxidizing agent.

(D)${\mathrm{Sn}}^{2+}$

1. The reduction potential of ${\mathrm{Sn}}^{2+}$ is -0.16V.
2. As the reduction potential of ${\mathrm{Sn}}^{2+}$is quite high so it is a good oxidizing agent. ${\mathrm{Sn}}^{2+}\left(\mathrm{aq}\right)+2{\mathrm{e}}^{-}\to \mathrm{Sn}\left(\mathrm{s}\right)$
3. It is a good oxidizing agent but has a low value of reduction potential than that of ${\mathrm{Pb}}^{2+}$.

Therefore, option A is correct. ${\mathrm{Pb}}^{2+}$is the best oxidizing agent.