Calculate E°_cell for each balanced redox reaction and determine if the reaction is spontaneous as written. c. PbO₂(s) + 4 H⁺(aq) + Sn(s) → Pb²⁺(aq) + 2 H₂O(l) + Sn²⁺(aq)

Verified step by step guidance

1. Identify the half-reactions involved in the redox process. For the given reaction, the half-reactions are: PbO_2(s) + 4H^+(aq) + 2e^- \rightarrow Pb^{2+}(aq) + 2H_2O(l) and Sn(s) \rightarrow Sn^{2+}(aq) + 2e^-.
2. Look up the standard reduction potentials (E°) for each half-reaction from a standard reduction potential table. The standard reduction potential for PbO_2 to Pb^{2+} is typically positive, while for Sn to Sn^{2+} it is negative.
3. Calculate the standard cell potential (E°_{cell}) by using the formula: E°_{cell} = E°_{cathode} - E°_{anode}. Identify which half-reaction is the reduction (cathode) and which is the oxidation (anode).
4. Determine the spontaneity of the reaction. If E°_{cell} is positive, the reaction is spontaneous as written. If it is negative, the reaction is non-spontaneous.
5. Summarize the findings: State the calculated E°_{cell} and whether the reaction is spontaneous or not based on the sign of E°_{cell}.

Key Concepts

Standard Electrode Potential (Ec°ell)

The standard electrode potential, Ec°ell, is a measure of the tendency of a chemical species to be reduced, expressed in volts. It is determined under standard conditions (1 M concentration, 1 atm pressure, and 25°C). A positive Ec°ell indicates a spontaneous reaction, while a negative value suggests non-spontaneity. Calculating Ec°ell involves using the standard reduction potentials of the half-reactions involved in the redox process.

Redox Reactions

Redox reactions involve the transfer of electrons between two species, where one is oxidized (loses electrons) and the other is reduced (gains electrons). In the given reaction, lead dioxide (PbO2) is reduced to lead ions (Pb2+), while tin (Sn) is oxidized to tin ions (Sn2+). Understanding the oxidation states and identifying the oxidizing and reducing agents are crucial for balancing the reaction and calculating Ec°ell.

Spontaneity of Reactions

The spontaneity of a reaction refers to its ability to occur without external intervention. In electrochemistry, a reaction is spontaneous if the calculated standard cell potential (Ec°ell) is positive. This indicates that the free energy change (ΔG) for the reaction is negative, favoring the formation of products. Evaluating the spontaneity helps predict whether the reaction will proceed as written under standard conditions.