Faraday's laws Knowledge-Based Download PDF

Questions

1. 1.

   How many seconds are required to deposit 2.70 g of aluminum at the cathode during the electrolysis of molten $\text{Al}_2\text{O}_3$ using a steady current of 96.5 A? (Atomic mass of $\text{Al} = 27.0\text{ g/mol}$, Faraday's constant $F = 96\,500\text{ C/mol }e^-$)

   • A) 300 s
   • B) 100 s
   • C) 600 s
   • D) 900 s
2. 2.

   A constant electric current of 9.65 A is passed through an electrolytic cell containing a molten salt of an unknown metal $M^{n+}$ for 50.0 minutes, depositing 0.100 mol of metal $M$ at the cathode. What is the value of $n$, representing the oxidation state of the metal ion? (Faraday's constant $F = 96\,500\text{ C/mol }e^-$)

   • A) +1
   • B) +2
   • C) +3
   • D) +4
3. 3.

   During the electrolysis of dilute sulfuric acid, an electric charge of 19,300 C is passed through the cell. What volume of oxygen gas ($\text{O}_2$) is liberated at the anode at standard temperature and pressure (STP)? (Faraday's constant $F = 96,500\text{ C/mol }e^-$; molar volume of gas at STP = 22.4 L/mol)

   • A) 1.12 L
   • B) 2.24 L
   • C) 4.48 L
   • D) 0.56 L
4. 4.

   Two electrolytic cells containing molten $\text{AlCl}_3$ and molten $\text{NaCl}$ are connected in series. If 5.4 g of aluminum metal is deposited at the cathode of the first cell, what mass of sodium metal is deposited at the cathode of the second cell? ($\text{Al} = 27\text{ g/mol}$, $\text{Na} = 23\text{ g/mol}$)

   • A) 4.6 g
   • B) 6.9 g
   • C) 13.8 g
   • D) 41.4 g
5. 5.

   A constant electric current of $9.65\text{ A}$ is passed through an aqueous copper(II) sulfate solution for $1000\text{ seconds}$. What mass of copper metal is deposited at the cathode? ($\text{Cu} = 64\text{ g/mol}$, Faraday's constant $F = 96\,500\text{ C/mol } e^-$)

   • A) 3.2 g
   • B) 6.4 g
   • C) 1.6 g
   • D) 12.8 g