/
AI Flashcards
Save to my account
Sign up
Report Bug
AI Flashcards
Molten Sodium Chloride Electrolysis
Study
Question
Which species is reduced at the cathode during electrolysis of molten sodium chloride?
Page 3
Answer
\$Na^+\$ is reduced to elemental sodium: \$2Na^+ + 2e^- \rightarrow 2Na\$.
Question
Which species is oxidized at the anode during electrolysis of molten sodium chloride?
Page 3
Answer
\$Cl^-\$ is oxidized to chlorine gas: \$2Cl^- \rightarrow Cl_2 + 2e^-\$.
Question
Write the overall chemical equation for the electrolysis of molten sodium chloride.
Page 3
Answer
\$2NaCl \rightarrow 2Na + Cl_2\$ (electricity is required to drive this non-spontaneous reaction).
Question
In the external circuit of the electrolytic cell, which direction do electrons flow during electrolysis of molten NaCl?
Page 3
Answer
Electrons flow from the anode to the cathode through the external circuit (produced at the anode, consumed at the cathode).
Question
Which direction do \$Na^+\$ ions move inside molten NaCl during electrolysis and why?
Page 3
Answer
\$Na^+\$ ions migrate toward the cathode so they can gain electrons and be reduced to \$Na\$.
Question
Which direction do \$Cl^-\$ ions move inside molten NaCl during electrolysis and why?
Page 3
Answer
\$Cl^-\$ ions migrate toward the anode so they can lose electrons and be oxidized to \$Cl_2\$.
Question
Define the anode and cathode in the context of the molten NaCl electrolytic cell.
Page 3
Answer
Anode: the electrode where oxidation occurs (chloride ions oxidize to \$Cl_2\$). Cathode: the electrode where reduction occurs (sodium ions reduce to \$Na\$).
Question
In an electrolytic cell performing molten NaCl electrolysis, which electrode is connected to the positive terminal of the external power supply?
Page 3
Answer
The anode is connected to the positive terminal of the power supply; the cathode is connected to the negative terminal.
Question
What physical products appear at the cathode and anode during electrolysis of molten NaCl?
Page 3
Answer
At the cathode: molten elemental sodium (liquid metal). At the anode: chlorine gas bubbles (\$Cl_2\$).
Question
Why must sodium chloride be molten (or dissolved) to undergo electrolysis?
Page 3
Answer
Molten (or dissolved) sodium chloride provides mobile ions (\$Na^+\$ and \$Cl^-\$) that can migrate to the electrodes and conduct current; solid ionic crystals do not allow ion mobility.
Question
How many electrons are transferred in the pair of half-reactions for the electrolysis of two moles of NaCl to give \$2Na\$ and \$Cl_2\$?
Page 3
Answer
Two electrons are transferred: the anode half-reaction releases 2 e^- (\$2Cl^- \rightarrow Cl_2 + 2e^-\$) and the cathode half-reaction consumes 2 e^- (\$2Na^+ + 2e^- \rightarrow 2Na\$).
Question
Describe the change in oxidation number for sodium and chlorine during the electrolysis of molten NaCl.
Page 3
Answer
Sodium: oxidation number changes from +1 in \$Na^+\$ to 0 in \$Na\$ (reduction). Chlorine: oxidation number changes from -1 in \$Cl^-\$ to 0 in \$Cl_2\$ (oxidation).