ELECTROLYSIS -- 5.4.3.4 Electrolysis of aqueous solutions Flashcards
(24 cards)
What does aqueous (aq) mean?
Aqueous means a substance is dissolved in water.
What ions are added during the electrolysis of aqueous solutions?
H⁺ (hydrogen) and OH⁻ (hydroxide) ions.
What happens to ions in electrolysis of aqueous solutions?
Ions from the compound move to the electrodes.
What happens to water molecules during electrolysis?
Water molecules break down, adding H⁺ and OH⁻ ions.
What is discharged at each electrode during electrolysis?
The less reactive ion.
What forms at the cathode (-) during electrolysis?
Either a metal or hydrogen gas.
What happens if the metal is less reactive than hydrogen?
The metal is deposited.
What happens if the metal is more reactive than hydrogen?
Hydrogen gas (H₂) is produced.
What is the cathode product when electrolysis of copper sulfate (CuSO₄) occurs?
Copper (Cu).
What is the cathode product when electrolysis of sodium chloride (NaCl) occurs?
Hydrogen (H₂).
What is the equation for hydrogen forming at the cathode?
2H⁺ + 2e⁻ → H₂
What forms at the anode (+) during electrolysis?
Either oxygen or a halogen (Cl₂, Br₂, I₂).
What happens if halide ions are present at the anode?
A halogen is produced.
What happens if no halide ions are present at the anode?
Oxygen (O₂) forms from OH⁻ ions.
What is the anode product when electrolysis of copper sulfate (CuSO₄) occurs?
Oxygen (O₂).
What is the anode product when electrolysis of sodium chloride (NaCl) occurs?
Chlorine (Cl₂).
What is the equation for oxygen forming at the anode?
4OH⁻ → O₂ + 2H₂O + 4e⁻
What are the final products of the electrolysis of sodium chloride (NaCl) solution?
Hydrogen (H₂), Chlorine (Cl₂), and Sodium hydroxide (NaOH).
Fill in the blank: Aqueous solutions contain ______ and ______ ions from water.
H⁺ and OH⁻
True or False: If a metal is more reactive than hydrogen, hydrogen forms at the cathode.
True
True or False: If halide ions are present, oxygen forms at the anode.
False
What is produced at the anode if chloride ions (Cl⁻) are present?
Chlorine gas (Cl₂).
What is produced at the anode if no halide ions are present?
Oxygen gas (O₂).
What is the significance of water breaking down during electrolysis?
It contributes H⁺ and OH⁻ ions that can also be discharged.
