In view of the signs of `Delta_(r)G^(0)` for the following reactions
`PbO_(2)+Pbrarr2PbO,Delta_(r)G^(0)lt0`
`SnO_(2)+Snrarr2SnO,Delta_(r)G^(0)gt0`
Which oxidation state are more characteristic for lead and tin?

Options

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

D

Explanation

`{:(,PbO_(2),+,Pb,rarr,2PbO),("Oxidation state",+4,,0,,+2):}`
Since, `DeltaG^(@) lt 0`, i.e., it is negative.
therefore, the reaction is spontaneous in the forward direction. This suggest that `Pb^(2+)` is more stable than `Pb^(4+)`
`{:(,SnO_(2),+,Sn,rarr,2SnO),("Oxidation state",+4,,0,,+2):}`
Since, `DeltaG^(@) lt 0` i.e., it is positive.
Therefore, the reaction is non-spontaneous in the forward direction. but it will spontaneous in the backward direction. This suggests that `Sn^(2+)` is less stable than `Sn^(4+)`. These facts are also supported by the inert pair effect down the group.