Question

In view of the signs of ${△}_r{G}^{\circ }$ for the following reactions
$Pb{O}_2+Pb\to 2PbO,{△}_r{G}^{\circ }<0$,
$Sn{O}_2+Sn\to 2SnO,△G^{\circ }>0$
Which oxidation states are more characteristic for lead and tin?

• A. For lead $+4$, For tin $+2$
• B. For lead $+2$, For tin $+2$
• C. For lead $+4$, For tin $+4$
• D. For lead $+2$, For tin $+4$

Answer 1

Answer: (D)

For lead $+2$, For tin $+4$

$\begin{array}{c}Pb{O}_2\\ +4\end{array}+\begin{array}{c}Pb\\ 0\end{array}\begin{array}{c}\to \\ \end{array}\begin{array}{c}2PbO\\ +2\end{array}\Delta G>0Spontaneous+2ismorestable$

$\begin{array}{c}Sn{O}_2\\ +4\end{array}+\begin{array}{c}Sn\\ 0\end{array}\begin{array}{c}\to \\ \end{array}\begin{array}{c}2SnO\\ +2\end{array}\Delta G>0NonSpontaneous+2lessstable$

So for lead $+2$ and for $Sn$ $+4$

Option D is correct.