Question

In view of the signs of $\Delta$rG⁰ for the following reactions :

PbO2 + Pb$\rightarrow$ 2PbO, $\Delta$rG⁰< 0

SnO2 + Sn$\rightarrow$ 2SnO, $\Delta$rG⁰> 0,

which oxidation states are more characteristics for lead and tin ?

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

Answer 1

Answer: (C)

For lead +2, for tin +4

Answer 2

Negative $\Delta$rG⁰ value indicates that + 2 oxidation state is more stable for Pb2+ Also it is supported by inert pair effect that +2 oxidation state is more stable for Pb and + 4 oxidation state is more stable for Sn.