1
PbO2 PbO; G298 < 0 SnO2 SnO; G298 > 0 Most probable oxidation state of Pb and Sn will be
- Pb4+, Sn4+
- Pb4+, Sn2+
- Pb2+, Sn2+
- Pb2+, Sn4+
Answer
(4) Pb2+, Sn4+
Solution
PbO2 PbO has G < 0 ⇒ the change +4 +2 is spontaneous ⇒ Pb2+ is more stable.
SnO2 SnO has G > 0 ⇒ the change +4 +2 is non-spontaneous ⇒ Sn4+ is more stable.
As per NCERT, the inert pair effect increases down group 14, so +2 is the more stable state for Pb while +4 is more stable for Sn.
∴ Most probable oxidation states: Pb2+, Sn4+
Answer: (4)
AIPMT 2001