NEET Electrochemistry — Set 12

Question 1

How many coulombs are required to deposit 2.07 g of lithium from a LiCl solution? (Atomic mass of Li = 6.9 g/mol, F = 96500 C/mol)

Accepted Answer

$ Li^+ + e^- \rightarrow Li $. 1 mol Li (6.9 g) requires 1F. Moles = $ \frac{2.07}{6.9} = 0.3 \, mol $, Charge = $ 0.3 \times 96500 = 28950 \, C $.

Question 2

The limiting molar conductivity of SrCl$_2$ is 260 S cm$^2$ mol$^{-1}$. If $ \lambda^\circ_{Sr^{2+}} = 118 \, S \, cm^2 \, mol^{-1} $, what is $ \lambda^\circ_{Cl^-} $?

Accepted Answer

$ \Lambda_m^\circ = \lambda^\circ_{Sr^{2+}} + 2\lambda^\circ_{Cl^-} $. $ 260 = 118 + 2\lambda^\circ_{Cl^-} $, $ 2\lambda^\circ_{Cl^-} = 142 $, $ \lambda^\circ_{Cl^-} = 71 \, S \, cm^2 \, mol^{-1} $.

Question 3

A cell has $ E^\circ_{cell} = 0.59 \, V $ and an equilibrium constant of $ 10^{20} $ at 298 K. How many electrons are transferred?

Accepted Answer

$ E^\circ_{cell} = \frac{0.059}{n} \log K_c $, $ 0.59 = \frac{0.059}{n} \times 20 $, $ n = \frac{1.18}{0.59} = 2 $.

NEET Chemistry: Electrochemistry — Practice Set 12

Q1. How many coulombs are required to deposit 2.07 g of lithium from a LiCl solution? (Atomic mass of Li = 6.9 g/mol, F = 96500 C/mol)

Q2. The limiting molar conductivity of SrCl\(_2\) is 260 S cm\(^2\) mol\(^{-1}\). If \( \lambda^\circ_{Sr^{2+}} = 118 \, S \, cm^2 \, mol^{-1} \), what is \( \lambda^\circ_{Cl^-} \)?

Q3. A cell has \( E^\circ_{cell} = 0.59 \, V \) and an equilibrium constant of \( 10^{20} \) at 298 K. How many electrons are transferred?

Q4. What is the potential of a hydrogen electrode in a solution with pH = 7 at 298 K? (Given: \( E^\circ_{H^+/H_2} = 0.00 \, V \))

Q5. A cell has \( E^\circ_{cell} = 0.88 \, V \) and \( \Delta_r G^\circ = -169840 \, J/mol \) at 298 K. How many electrons are transferred? (F = 96500 C/mol)

Q6. What is the standard cell potential for the galvanic cell where zinc is oxidized and copper ions are reduced, given the standard electrode potentials of Zn\(^{2+}/Zn\) = -0.76 V and Cu\(^{2+}/Cu\) = 0.34 V?

Q7. In the electrolysis of aqueous NaCl with inert electrodes, what gas is produced at the anode?

Q8. How many coulombs are required to deposit 0.27 g of aluminum from Al(NO\(_3\))\(_3\) solution? (Atomic mass of Al = 27 g/mol, F = 96500 C/mol)

Q9. In a fuel cell using H\(_2\) and O\(_2\), what is the product of the overall reaction?

Q10. In a lead storage battery, what is the product formed at both electrodes during discharge?