Question
Chemistry Question on p -Block Elements
PbO2 → PbO ∆G298< 0,
SnO2 → SnO ∆G298 > 0,
Most probable oxidation state of Pb & Sn will be
A
Pb+4, Sn+2
B
Pb+4, Sn+2
C
Pb+2, Sn+2
D
Pb+2, Sn+4
Answer
Pb+2, Sn+4
Explanation
Solution
The correct option is (D): Pb+2, Sn+4.
The most probable oxidation states of Pb and Sn are Pb²⁺ and Sn⁴⁺ because PbO2 → PbO has a negative change in Gibbs free energy (∆G298 < 0), indicating a reduction reaction where Pb goes from a higher oxidation state to a lower one. Similarly, SnO2 → SnO has a positive (∆G298 > 0), indicating an oxidation reaction where Sn goes from a lower oxidation state to a higher one.