Electrolysis Flashcards
What is electrolysis?
The process of using an electrical current to cause a chemical reaction in a molten or dissolved ionic compound.
What happens to positive ions during electrolysis?
Positive ions move towards the cathode, gain electrons, and are reduced.
What happens to negative ions during electrolysis?
Negative ions move towards the anode, lose electrons, and are oxidized.
Why does electrolysis create a flow of charge?
Because ions travel through the electrolyte as they move to the electrodes.
What do ions form after they gain or lose electrons during electrolysis?
They form the uncharged element and are discharged from the electrolyte.
Why can’t an ionic solid be electrolysed?
The ions are in fixed positions and can’t move.
Under what condition can ionic compounds be electrolysed?
When they are molten, allowing ions to move freely and conduct electricity.
What happens to a positive metal ion at the cathode during electrolysis of molten ionic solids?
It is reduced to form the element at the cathode.
What happens to a negative non-metal ion at the anode during electrolysis of molten ionic solids?
It is oxidized to form the element at the anode.
Why is electrolysis used to extract metals from their ores?
For metals that are too reactive to be reduced with carbon or react with carbon.
Why is cryolite added to aluminum oxide during electrolysis?
To lower the melting point of aluminum oxide, which has a very high melting temperature.
What is the role of the molten mixture in aluminum extraction?
It contains free ions, allowing the mixture to conduct electricity.
Where do positive Al3+ ions go during electrolysis?
To the negative electrode, where they pick up three electrons and turn into neutral aluminum atoms.
What happens to negative O2- ions during aluminum extraction electrolysis?
They move to the positive electrode, lose two electrons, and form oxygen atoms.
What do oxygen atoms form after losing electrons at the positive electrode?
They combine to form O2 molecules.
