Question
It is noticed that Pb ^ 2+ is more stable than Pb ^ 4+ but Sn ^ 2+ is less stable than Sn ^ 4+ . Observe the following reactions. PbO _ 2 + Pb 2 PbO ; _ r G ^ (1) SnO _ 2 + Sn 2 SnO ; _ r G ^ (2) Identify the correct set from the following
JEE Main
Chemistry
p Block Elements (Group 13 & 14)
2026
JEE Main 2026 (23 January Shift 2)
JEE Main Chemistry Question (2026) — Solution
Options
- A. _ r G ^ (1)<0 ; _ r G ^ (2)<0
- B. _ r G ^ (1)>0 ; _ r G ^ (2)>0
- C. _ r G ^ (1) 0
- D. _ r G ^ (1)>0 ; _ r G ^ (2)<0
Answer
C. _ r G ^ (1) 0
Step-by-step solution
The stability of oxidation states in Group 14 is governed by the inert pair effect, which increases down the group. For Lead (Pb), the +2 oxidation state is more stable than the +4 state (Pb^ 2+ > Pb^ 4+ ). In the reaction PbO_2 + Pb 2PbO, Pb^ 4+ is being reduced to Pb^ 2+ and Pb^0 is being oxidized to Pb^ 2+ . Since the product contains the more stable oxidation state, the reaction is spontaneous, meaning _r G^ (1) For Tin (Sn), the +4 oxidation state is more stable than the +2 state (Sn^ 4+ > Sn^ 2+ ). In the reaction SnO_2 + Sn 2SnO, the stable Sn^ 4+ is being converted into the less stable Sn^ 2+ . This process is non-spontaneous, meaning _r G^ (2) > 0. Thus, the correct set is _r G^ (1) 0.
Related: Chemistry — p Block Elements (Group 13 & 14) · All PYQ Banks