Consider the following chemical reactions involving the elements of Group 14: (I) Sn²⁺ + 2Fe³⁺ Sn⁴⁺ + 2Fe²⁺ (II) PbO₂ + 4HCl PbCl₂ + Cl₂ + 2H₂O (III) Sn⁴⁺ + Pb²⁺ Sn²⁺ + Pb⁴⁺ (IV) PbCl₄ PbCl₂ + Cl₂ Which of the above reactions is NOT thermodynamically feasible under standard conditions?

Step-by-step solution

Due to the inert pair effect, the stability of the +2 oxidation state increases and the stability of the +4 oxidation state decreases down Group 14. For Tin (Sn), the +4 state is more stable than the +2 state, making Sn²⁺ a good reducing agent (it readily oxidises to Sn⁴⁺ ). For Lead (Pb), the +2 state is more stable than the +4 state, making Pb⁴⁺ a strong oxidising agent (it readily reduces to Pb²⁺ ). Reaction (I) involves the oxidation of Sn²⁺ to Sn⁴⁺ , which is feasible. Reactions (II) and (IV) involve the reduc