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39 questions
It is essential that the electrolyte is a liquid so that...
Charged ions can migrate towards the electrodes.
Charged ions can migrate towards the electrodes.
The solution can move around.
The current can flow through it.
Why is electrolysis of aqueous (dissolved) solutions more complicated than molten?
Water is messy
Water contributes hydrogen and hydroxide ions to the electrolyte
It is easier to dissolve some substances in water than to melt them
In an aqueous solution of copper chloride, which substance is produced at the negative electrode
copper
chlorine
oxygen
chloride
A
B
C
D
A
B
C
D
A
B
C
D
The electrodes in electrolysis of aluminium are made of
Steel
Anodes
Graphite
Plastic
What do you add to aluminium ore to reduce its melting temperature?
Dendrite
Malachite
Bauxite
Cryolite
Anions get discharged by ________ electrons at the ___________
gaining, cathode
losing, anode
gaining, anode
losing, cathode
What is the gas produced at the anode during the electrolysis of very dilute hydrochloric acid?
water
oxygen
hydrogen
chlorine
Choose the half-equation that shows the discharge of aluminium ion.
Al3+ - 3e- --> Al
Al2+ + 3e- --> Al
Al3+ + 3e- --> Al
Al3+ --> Al + 3e-
What is the half-equation for the discharge of hydroxide ions?
2O2- --> O2 + 4e-
OH- --> OH + e
4OH- --> 2H2O + O2 + 4e-
2H2O + O2 + 4e- --> 4OH-
What ions are present in molten aluminium oxide?
Al3+, O2-, H+, OH-
Al3+, O2-
Al3+, OH-
The picture shows electrolysis of copper(II) sulphate solution using graphite electrodes. Besides formation of brown solid on the cathode, what other observations can be made?
The mass of graphite anode decreases.
The blue colour solution becomes paler.
Bubbles of gas form at the anode.
The blue colour solution becomes darker.
Oxidation is loss of electron. Where does oxidation take place during electrolysis.
At anode
In the solution
At cathode
In the circuit
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