Electrolysis of Ionic Compounds

Electrolysis

• Electrolysis is the process of decomposing a molten or aqueous ionic compound using an electric current
• This process also occurs for aqueous solutions of ionic compounds
• Liquids/solutions that can conduct electricity are called electrolytes
• Covalent compounds cannot conduct electricity, thus do not undergo electrolysis
• An electrolytic cell consists of an electrode (metal or graphite for conducting electricity into/out of the electrolyte) and an electrolyte (ionic compound in a molten or dissolved solution that conducts electricity)
• The anode is the positive electrode, and the cathode is the negative electrode
• Anions (negatively charged ions) are attracted to the anode
• Cations (positively charged ions) are attracted to the cathode

Ionic Compounds

• Ionic compounds in the solid state cannot conduct electricity because they have no free ions to move and carry the charge
• Ions can move and carry charge when molten or dissolved in a solution (typically aqueous)
• When the electrolyte is placed in an electrolytic cell, the ions move towards the electrodes when a current is passed through it

Electrolysis Process

• Electrons move from the power supply to the cathode
• Electron flow in electrochemistry occurs in alphabetical order: from the anode to the cathode
• Positive ions migrate to the negatively charged cathode
• Negative ions migrate to the positively charged anode
• When a metal conducts, electrons move through it; when a salt solution conducts, ions in the solution move towards the electrodes while carrying the electrons

Predicting Products of Electrolysis

• For binary molten compounds, identify the ions present
• Positive ions migrate to the cathode; negative ions migrate to the anode
• The cathode product is always the metal
• The anode product is always the non-metal

Electrodes

• Electrodes such as graphite or platinum are inert so they do not react with the electrolyte

This quiz explores the fundamental concepts of electrolysis, focusing on the behavior of ionic compounds in molten and aqueous states. Learn about the distinctions between electrolytes and covalent compounds, and how ions behave during the electrolysis process. Test your understanding of electrodes, anodes, and cathodes in this essential chemistry topic.