Given: Ag⁺(aq)+ e^- → Ag(s)E° = +0.799 V AgI(s)+ e^- → Ag(s)+ I^-(aq)E° = -0.152 V Ni²⁺(aq)+ 2 e^- → Ni(s)E° = -0.267 V Which of the following reactions should be spontaneous under standard conditions? I.2 AgI(s)+ Ni(s)→ 2 Ag(s)+ 2 I^-(aq)+ Ni²⁺(aq) II.Ag+(aq)+ I^-(aq)→ AgI(s)

Question

Quizplus · Accepted Answer

To determine the spontaneity of the reactions under standard conditions, we can use the standard electrode potentials (E°) given for the half-reactions. The overall cell potential (E°cell) for a reaction can be calculated by subtracting the E° of the oxidation half-reaction from the E° of the reduction half-reaction. A positive E°cell indicates a spontaneous reaction.For reaction I, combining the half-reactions for AgI and Ni gives us an overall reaction. The E° for AgI → Ag + I- is -0.152 V (given as a reduction potential, so the reverse reaction, Ag + I- → AgI, would have E° = +0.152 V for oxidation). The E° for Ni2+ + 2e- → Ni is -0.267 V (given as a reduction potential, so this is the oxidation half-reaction in this context). To find the overall E°cell for reaction I, we add the E° values of the half-reactions (since one is considered in the reverse direction for oxidation): E°cell = +0.152 V - (-0.267 V) = +0.419 V. A positive E°cell indicates that reaction I is spontaneous.For reaction II, the formation of AgI(s) from Ag+ and I- is essentially the reverse of the AgI dissolution reaction given, which has an E° = -0.152 V. Since the given E° is for the dissolution (AgI → Ag+ + I-), the reverse reaction (Ag+ + I- → AgI) would have the same magnitude but opposite sign for the E° value, making it +0.152 V, indicating that reaction II is also spontaneous under standard conditions.Therefore, both reactions I and II are spontaneous under standard conditions.

Given: Ag+(aq)+ E- → Ag(s)E° = +0

Given: Ag⁺(aq)+ E^- → Ag(s)E° = +0