NEET Electrochemistry — Set 11

Question 1

The emf of a cell $ Fe(s) | Fe^{2+}(0.001 \, M) || Cu^{2+}(0.1 \, M) | Cu(s) $ at 298 K is (Given: $ E^\circ_{Fe^{2+}/Fe} = -0.44 \, V $, $ E^\circ_{Cu^{2+}/Cu} = 0.34 \, V $)?

Accepted Answer

$ E^\circ_{cell} = 0.34 - (-0.44) = 0.78 \, V $. $ E_{cell} = 0.78 - \frac{0.059}{2} \log \frac{0.001}{0.1} = 0.78 + 0.059 = 0.839 \, V $.

Question 2

What is the standard emf of a cell with the reaction $ Co(s) + Ni^{2+}(aq) \rightarrow Co^{2+}(aq) + Ni(s) $? (Given: $ E^\circ_{Co^{2+}/Co} = -0.28 \, V $, $ E^\circ_{Ni^{2+}/Ni} = -0.25 \, V $)

Accepted Answer

$ E^\circ_{cell} = E^\circ_{cathode} - E^\circ_{anode} = -0.25 - (-0.28) = 0.03 \, V $.

Question 3

The standard Gibbs energy change for a cell reaction is -212.27 kJ/mol, and 2 electrons are transferred. What is the standard emf of the cell? (F = 96500 C/mol)

Accepted Answer

$ \Delta_r G^\circ = -n F E^\circ_{cell} $. $ -212270 = -2 \times 96500 \times E^\circ_{cell} $, $ E^\circ_{cell} = 1.1 \, V $.

NEET Chemistry: Electrochemistry — Practice Set 11

Q1. The emf of a cell \( Fe(s) | Fe^{2+}(0.001 \, M) || Cu^{2+}(0.1 \, M) | Cu(s) \) at 298 K is (Given: \( E^\circ_{Fe^{2+}/Fe} = -0.44 \, V \), \( E^\circ_{Cu^{2+}/Cu} = 0.34 \, V \))?

Q2. What is the standard emf of a cell with the reaction \( Co(s) + Ni^{2+}(aq) \rightarrow Co^{2+}(aq) + Ni(s) \)? (Given: \( E^\circ_{Co^{2+}/Co} = -0.28 \, V \), \( E^\circ_{Ni^{2+}/Ni} = -0.25 \, V \))

Q3. The standard Gibbs energy change for a cell reaction is -212.27 kJ/mol, and 2 electrons are transferred. What is the standard emf of the cell? (F = 96500 C/mol)

Q4. A galvanic cell has \( E^\circ_{cell} = 0.62 \, V \). If the cell potential becomes 0.68 V at 298 K when \( [Oxidized] = 0.01 \, M \) and \( [Reduced] = 0.1 \, M \), how many electrons are transferred?

Q5. In a mercury cell, 0.34 g of Zn (atomic mass 68 g/mol) is oxidized at the anode. What mass of Hg (atomic mass 200 g/mol) is produced at the cathode? (F = 96500 C/mol)

Q6. A mercury cell produces 0.5 g of Hg (atomic mass 200 g/mol) at the cathode. What mass of Zn (atomic mass 68 g/mol) is oxidized at the anode? (F = 96500 C/mol)

Q7. In a lead storage battery during discharge, what is the oxidation state of lead in the cathode product?

Q8. How many Faradays are required to deposit 27 g of aluminum from molten Al\(_2\)O\(_3\)? (Atomic mass of Al = 27 g/mol)

Q9. The conductivity of a 0.002 M weak electrolyte solution is 8 × 10\(^{-5}\) S cm\(^{-1}\). What is its molar conductivity?

Q10. In a fuel cell, what is the oxidizing agent?