NEET Electrochemistry — Set 14

Question 1

What is the potential of a hydrogen electrode in a solution with pH = 10 at 298 K? (Given: $ E^\circ_{H^+/H_2} = 0.00 \, V $)

Accepted Answer

$ E = E^\circ - \frac{0.059}{n} \log \frac{1}{[H^+]} $, $ [H^+] = 10^{-10} $, $ n = 1 $. $ E = 0 - 0.059 \times 10 = -0.59 \, V $.

Question 2

In the electrolysis of dilute H$_2$SO$_4$ with Pt electrodes, what gas is liberated at the cathode?

Accepted Answer

Cathode: $ 2H_2O + 2e^- \rightarrow H_2 + 2OH^- $. Hydrogen gas is liberated.

Question 3

In electrolysis of molten NaF, 0.23 g of Na (atomic mass 23 g/mol) is deposited. What volume of F$_2$ gas (STP) is produced at the anode? (F = 96500 C/mol)

Accepted Answer

Cathode: $ Na^+ + e^- \rightarrow Na $, Moles = $ \frac{0.23}{23} = 0.01 \, mol $, Charge = $ 0.01 \times 96500 = 965 \, C $. Anode: $ 2F^- \rightarrow F_2 + 2e^- $, Moles F$_2$ = $ \frac{0.01}{2} = 0.005 \, mol $, Volume = $ 0.005 \times 22.4 = 0.112 \, L $.

NEET Chemistry: Electrochemistry — Practice Set 14

Q1. What is the potential of a hydrogen electrode in a solution with pH = 10 at 298 K? (Given: \( E^\circ_{H^+/H_2} = 0.00 \, V \))

Q2. In the electrolysis of dilute H\(_2\)SO\(_4\) with Pt electrodes, what gas is liberated at the cathode?

Q3. In electrolysis of molten NaF, 0.23 g of Na (atomic mass 23 g/mol) is deposited. What volume of F\(_2\) gas (STP) is produced at the anode? (F = 96500 C/mol)

Q4. A hydrogen electrode operates at 298 K with \( P_{H_2} = 0.5 \, atm \) and pH = 3. What is its potential? (Given: \( E^\circ_{H^+/H_2} = 0.00 \, V \))

Q5. A current of 0.2 A deposits 0.127 g of Cu from CuSO\(_4\) in 9650 s. What is the current required to deposit 0.27 g of Al from AlCl\(_3\) in the same time? (Atomic masses: Cu = 63.5 g/mol, Al = 27 g/mol, F = 96500 C/mol)

Q6. In a mercury cell, what is the product at the anode during discharge?

Q7. In a fuel cell using H\(_2\) and O\(_2\), what is the anode reaction?

Q8. A cell \( Ni(s) | Ni^{2+}(0.002 \, M) || Cl_2(g)(0.5 \, atm) | Cl^-(0.05 \, M) | Pt(s) \) operates at 298 K. What is the cell potential? (Given: \( E^\circ_{Ni^{2+}/Ni} = -0.25 \, V \), \( E^\circ_{Cl_2/Cl^-} = 1.36 \, V \))

Q9. In a lead storage battery, what is the cathode material?

Q10. What is the emf of the cell \( Co(s) | Co^{2+}(0.01 \, M) || Ag^+(0.001 \, M) | Ag(s) \) at 298 K? (Given: \( E^\circ_{Co^{2+}/Co} = -0.28 \, V \), \( E^\circ_{Ag^+/Ag} = 0.80 \, V \))