Q14(a). Which pairs of Fe³⁺/Fe²⁺ and Sn⁴⁺/Sn²⁺ react
The standard electrode potentials for the two half-reactions are given below: Fe³⁺ + e⁻ ⇌ Fe²⁺, E° = 0.771 V; Sn⁴⁺ + 2e⁻ ⇌ Sn²⁺, E° = 0.154 V. Explain if the following reactions are possible or not: (i) Reaction between Fe²⁺ and Sn⁴⁺; (ii) Reaction between Fe²⁺ and Sn²⁺; (iii) Reaction between Fe³⁺ and Sn²⁺; (iv) Reaction between Sn⁴⁺ and Fe²⁺.
Answer in brief
Only (iii), Fe³⁺ with Sn²⁺, is possible (E° = +0.617 V). (i) and (iv), the same pair, are not possible (E° = −0.617 V). (ii) gives no reaction: both ions are reductants.
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Coversstandard electrode potentialfeasibility of redox reactionsFe3+/Fe2+Sn4+/Sn2+ΔG = −nFE
All parts of Question 14
- 14(a) Which pairs of Fe³⁺/Fe²⁺ and Sn⁴⁺/Sn²⁺ react10 marks
- 14(b) Spontaneous reaction: cell, E°cell and K at 298 K10 marks