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

`Pboverset(+4)O_2 +Pb rarr 2 overset(+2)(PbO) As Delta_r G^@ lt 0. ` I.e it is -ve. The reaction is spontaneous in the forward direction i.e `Pb^(+2)` is more stalbe than `Pb^(+4)`
`Snoverset(+4)O_2+Sn rarr 2 Sn overset(+2)(O). As Delta_r G^@ gt 0,` i,e it is positive reverse reacction will be spontaneous i.e `Sn^(+4)` will be more stable than `Sn^(2+)` . These facts are also supported by the inert pair effect down the group.