Question

Answer the following questions related to the given electrochemical cell under standard conditions.

W3+(aq) + 3e− ⇌ W(s) E° = 0.100 V	Co2+(aq) + 2e− ⇌ Co(s) E° = -0.280 V

1. Answer the following questions.

(a) The half cell containing W/W³⁺ is the  anode/ cathode

(b) Which one of the following statements isTRUE for the half cell containing W and W³⁺.
W³⁺ will be oxidized to form W.
W³⁺ will be reduced to form W.
W will be reduced to form W³⁺.
W will be oxidized to form W³⁺.

(c) The half cell containing Co²⁺/Co is the  anode/ cathode

(d) Which one of the following statements isTRUE for the half cell containing Co and Co²⁺.
Co will be reduced to form Co²⁺.
Co will be oxidized to form Co²⁺.
Co²⁺ will be reduced to form Co.
Co²⁺ will be oxidized to form Co.

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2. What is E°_cell (in V)? Report your answer to three decimal places in standard notation (i.e., 0.123 V).

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3. Answer the following questions.

(a) Which one of the following is the balanced chemical equation for the spontaneous process occurring in the electrochemical cell under standard conditions?
3W³⁺(aq) + 2Co(s) → 3W(s) + 2Co²⁺(aq).
2W(s) + 3Co²⁺(aq) → 2W³⁺(aq) + 3Co(s).
3W(s) + 2Co²⁺(aq) → 3W³⁺(aq) + 2Co(s).
2W³⁺(aq) + 3Co(s) → 2W(s) + 3Co²⁺(aq).

(b) How many electrons are being transferred in this balanced chemical reaction?

(c) What is ΔG° (in kJ/mol)? Report answer to three significant figures in scientific notation (i.e., 1.23e2 kJ/mol)

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4. If the reaction was allowed to proceed, the mass of the W electrode will (increase /decrease ) and the mass of the Co electrode will (increase/ decrease ) . The [W³⁺] in solution will ( increase /decrease) and the [Co²⁺] in solution will (increase/ decrease)

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5. The salt bridge contains K⁺ and Cl⁻. As the cell is in operation the K⁺ ions will tend to migrate toward the (anode /cathode) and the Cl⁻ ions will tend to migrate toward the ( anode/ cathode) . This occurs to counter balance any loss of ( W^3+ /Co^2+ ) ions as they precipitate onto the (W /Co) electrode

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Answer 1

W³⁺(aq) +3e^- = W(s), Here Reduction Occurs as W³⁺ is oxidized (loses 3 electrons) to form W(s).

The half-reaction on the cathode where reduction occurs. also there is +ve potential value E° = 0.100 V

Co(s) = Co^₂₊(aq) + 2e⁻ , Here Oxidation Occurs as Co(s) is reduced (gain 2 electrons) to form Co^₂₊(aq)

The half-reaction on the anode where Oxidation occurs. there is a negetive potential value E° = -0.280 V

Balance eqution,

W³⁺(aq) + Co(s) = W(s)+  Co_²⁺(aq)

3W³⁺(aq) + 2Co(s) → 3W(s) + 2Co²⁺(aq).

E_cell=E_cathode-E_anode = 0.100 V-(-0.280 V)=0.380V