NEET Electrochemistry — Set 18

Question 1

What is the equilibrium constant for a cell reaction with $ E^\circ_{cell} = 0.236 \, V $ at 298 K involving 2 electrons?

Accepted Answer

$ E^\circ_{cell} = \frac{0.059}{n} \log K_c $. $ 0.236 = \frac{0.059}{2} \log K_c $, $ \log K_c = 8, K_c = 10^8 $.

Question 2

The conductivity of a 0.025 M solution is 0.00325 S cm$^{-1}$. What is its molar conductivity?

Accepted Answer

$ \Lambda_m = \frac{\kappa \times 1000}{c} = \frac{0.00325 \times 1000}{0.025} = 130 \, S \, cm^2 \, mol^{-1} $.

Question 3

What is the standard cell potential for a galvanic cell where iron is oxidized and silver ions are reduced? (Given: $ E^\circ_{Fe^{2+}/Fe} = -0.44 \, V $, $ E^\circ_{Ag^+/Ag} = 0.80 \, V $)

Accepted Answer

Reaction: $ Fe(s) + 2Ag^+(aq) \rightarrow Fe^{2+}(aq) + 2Ag(s) $. $ E^\circ_{cell} = E^\circ_{cathode} - E^\circ_{anode} = 0.80 - (-0.44) = 1.24 \, V $.

NEET Chemistry: Electrochemistry — Practice Set 18

Q1. What is the equilibrium constant for a cell reaction with \( E^\circ_{cell} = 0.236 \, V \) at 298 K involving 2 electrons?

Q2. The conductivity of a 0.025 M solution is 0.00325 S cm\(^{-1}\). What is its molar conductivity?

Q3. What is the standard cell potential for a galvanic cell where iron is oxidized and silver ions are reduced? (Given: \( E^\circ_{Fe^{2+}/Fe} = -0.44 \, V \), \( E^\circ_{Ag^+/Ag} = 0.80 \, V \))

Q4. During electrolysis of aqueous Na\(_2\)SO\(_4\) with inert electrodes, 0.224 L of gas (STP) is collected at the cathode. How many coulombs were passed? (F = 96500 C/mol)

Q5. The conductivity of a 0.008 M solution is 0.00104 S cm\(^{-1}\). What is its molar conductivity?

Q6. The limiting molar conductivity of KBr is 151.8 S cm\(^2\) mol\(^{-1}\). If \( \lambda^\circ_{K^+} = 73.5 \, S \, cm^2 \, mol^{-1} \), what is \( \lambda^\circ_{Br^-} \)?

Q7. The resistance of a conductivity cell with 0.01 M NaCl solution is 250 Ω, and its conductivity is 0.0012 S cm\(^{-1}\). What is the cell constant?

Q8. What is the emf of the cell \( Cd(s) | Cd^{2+}(0.01 \, M) || Ni^{2+}(0.1 \, M) | Ni(s) \) at 298 K? (Given: \( E^\circ_{Cd^{2+}/Cd} = -0.40 \, V \), \( E^\circ_{Ni^{2+}/Ni} = -0.25 \, V \))

Q9. A lead storage battery is discharged with 2 A for 5 hours. What is the mass of PbO\(_2\) (molar mass 239 g/mol) consumed at the cathode? (F = 96500 C/mol)

Q10. In a lead storage battery, what is the anode material?