NEET Electrochemistry — Set 19

Question 1

The resistance of a conductivity cell with 0.02 M KCl solution is 400 Ω, and its conductivity is 0.0025 S cm$^{-1}$. What is the cell constant?

Accepted Answer

$ \kappa = \frac{\text{cell constant}}{R} $, $ 0.0025 = \frac{\text{cell constant}}{400} $, cell constant = 1.0 cm$^{-1} $.

Question 2

In a dry cell, what is the reducing agent during discharge?

Accepted Answer

Anode: $ Zn \rightarrow Zn^{2+} + 2e^- $. Zn is oxidized, so it’s the reducing agent.

Question 3

A weak electrolyte has $ \Lambda_m^\circ = 390 \, S \, cm^2 \, mol^{-1} $ and a degree of dissociation of 0.02 at 0.1 M. What is the conductivity of the solution?

Accepted Answer

$ \Lambda_m = \alpha \Lambda_m^\circ = 0.02 \times 390 = 7.8 \, S \, cm^2 \, mol^{-1} $. $ \kappa = \frac{\Lambda_m \times c}{1000} = \frac{7.8 \times 0.1}{1000} = 0.00078 \, S \, cm^{-1} $.

NEET Chemistry: Electrochemistry — Practice Set 19

Q1. The resistance of a conductivity cell with 0.02 M KCl solution is 400 Ω, and its conductivity is 0.0025 S cm\(^{-1}\). What is the cell constant?

Q2. In a dry cell, what is the reducing agent during discharge?

Q3. A weak electrolyte has \( \Lambda_m^\circ = 390 \, S \, cm^2 \, mol^{-1} \) and a degree of dissociation of 0.02 at 0.1 M. What is the conductivity of the solution?

Q4. What is the standard Gibbs energy change for a cell with \( E^\circ_{cell} = 1.05 \, V \) and 2 electrons transferred? (F = 96500 C/mol)

Q5. In the electrolysis of molten NaCl, what is the product at the cathode?

Q6. In electrolysis of molten MgCl\(_2\), 0.24 g of Mg (atomic mass 24 g/mol) is deposited. What volume of Cl\(_2\) gas (STP) is produced at the anode? (F = 96500 C/mol)

Q7. What is the equilibrium constant for a cell reaction with \( E^\circ_{cell} = 0.354 \, V \) at 298 K involving 2 electrons?

Q8. How many electrons are involved in the reduction of 1 mole of \( IO_3^- \) to \( I_2 \) in acidic medium?

Q9. The limiting molar conductivity of BaCl\(_2\) is 280 S cm\(^2\) mol\(^{-1}\). If \( \lambda^\circ_{Ba^{2+}} = 127 \, S \, cm^2 \, mol^{-1} \), what is \( \lambda^\circ_{Cl^-} \)?

Q10. What is the time (in seconds) required to deposit 1.175 g of sodium from molten NaCl using a current of 2 A? (Atomic mass of Na = 23.5 g/mol, F = 96500 C/mol)