Electrolytic processes Flashcards
What is an electrolyte?
Define aqueous?
An ionic compound in its molten or
aqueous state.
Aqueous - dissolved in water
Why can an electrolyte carry charge?
An ionic compound in is molten or
aqueous state has mobile ions which can
carry charge.
What is electrolysis?
Aprocess which uses electrical energy
(from a direct current supply) to
decompose electrolytes
What is the cathode and anode?
Cathode - negative electrode
Anode - positive electrode
Where do charged ions in the electrolyte move to
during electrolysis?
Cations (positive ions) move towards the
cathode (negative electrode).
Anions (negative ions) move towards the
anode (positive electrode).
What happens at the anode during electrolysis?
The anions (negatively charged ions) lose electrons to form their elements.
What happens at the cathode during electrolysis?
Cations (positively charged ions) gain
electrons to form their elements.
Name the processes that occur at each electrode
during electrolysis
Anode (positive) - oxidation.
Cathode (negative) - reduction
What is formed at each electrode in electrolysis?
Positive electrode (Anode): Non-metal. Negative electrode (Cathode): Metal or hydrogen.
How can you predict whether a metal or hydrogen
will form at the negative electrode?
If hydrogen is above the metal in
reactivity series then the metal will form.
If the metal is more reactive than
hydrogen then hydrogen will form
What is formed at each electrode during the
electrolysis of copper chloride solution?
Positive electrode: Chlorine
Negative electrode: Copper
What is formed at each electrode during the electrolysis of sodium sulfate solution?
Positive electrode: Oxygen
Negative electrode: Hydrogen
What is formed at each electrode during the
electrolysis of molten lead bromide?
Positive electrode: Bromine
Negative electrode: lead
Predict what will be formed at each electrode during
the electrolysis of molten zinc chloride
Positive electrode: Chlorine
Negative electrode: Zinc
What is formed at each electrode during the
electrolysis of sodium chloride solution?
Positive electrode: Chlorine
Negative electrode: Hydrogen
What is formed at each electrode during the
electrolysis of water acidified with sulfuric acid?
Positive electrode: Oxygen
Negative electrode: Hydrogen
What are the half equations for the reactions
occuring at the cathode and anode during the
electrolysis of copper chloride?
Anode: 2Cl- → Cl2 + 2e^-
Cathode: Cu^2+ + 2e- → Cu
What does oxidation mean in terms of electrons?
Loss of electrons
What does reduction mean in terms of electrons?
Gain of electrons
Describe how electrolysis of copper sulfate can be
used to purify copper
Place 2 copper electrodes into copper sulfate solution.
The anode should be impure copper and cathode should be pure copper.
Connect to a power supply.
The copper in the impure anode is pulled towards the cathode to form pure copper.
Impurities form as sludge below the anode.
Cu2+ ions from copper sulfate remain in solution.
Reactivity
https://i1.wp.com/www.expertguidance.co.uk/wp-content/uploads/2019/05/1-2.png?resize=248%2C800&ssl=1
