Electrolysis Flashcards
What does electrolysis mean?
Splitting up electricity.
What happens if you pass an electric current through an ionic substance that’s molten or in a solution?
It breaks down the elements its made of.
What does electrolysis require?
Liquid - To conduct the electricity. (An electrolyte)
What do electrolytes contain?
- Free electrons (Usually molten or dissolved iconic substance)
Free electrons…
Conduct electricity.
What is needed for an electrical circuit to be complete?
- Flow of electrons
What happens to ions as they gain or lose electrons at the positive electrode
They are given to other ions at the negative electrode. As ions lose or gain electrons they become atoms or molecules are released
Oxidation is…
LOSS of electrons
Reduction is…
GAIN of electrons
What a salt is molten it…
Will conduct electricity.
The electrolysis of molten lead bromide: where is the lead produced?
At the negative electrode.
In the electrolysis of molten lead bromide what are the +ve ions attracted too?
The -ve electrode
They GAIN electrons here
In the electrolysis of molten lead bromide what are the -ve ions attracted too?
The +ve ions
They LOSE electrons here
The electrolysis of molten lead bromide: where is the Bromine produced?
At the positive electrode.
In the electrolysis of molten lead bromide what happens at the -ve electrode?
One lead ions accepts two electrons to become one lead atom.
In the electrolysis of molten lead bromide what happens at the +ve electrode?
Two Bromide ions lose one electron each and become one bromide molecule.
What does radioactivity affect?
The products formed by electrolysis
Sometimes there are more than …… ions in the electrolyte
Two free
If a salt is dissolved in water what ions will be present?
H+ and OH-
What ions are present at the negative electrode
H+
The metal ions will stay in solution if the metal is more reactive than hydrogen
Hydrogen will be produced unless…
The metal is less reactive than it
What ions are present at the positive electrode
OH- and halide ions (CL-, Br-, I-)
If halide ions are present -> molecules of chlorine, bromine or iodine will form
If not -> Oxygen is formed
In the electrolysis of Sodium chloride solution what happens at the negative electrode?
Two hydrogen ions accept two electrons to become one hydrogen molecule.
In the electrolysis of Sodium chloride solution what happens at the positive electrode?
Two chloride (Cl-) ions lose their electrons and become one chlorine molecule.
In the electrolysis of Sodium chloride solution what happens to the sodium ions?
- Stay in solution (more reactive than hydrogen)
- Hydroxide ions from water are also left behind
- Sodium hydroxide (NaOH) is left in the solution
When sodium chloride is dissolved in water and electrolysed what does it produce?
3 Useful products:
- Hydrogen
- Chlorine
- Sodium hydroxide
In the electrolysis of Sodium chloride solution what is produced at the -ve electrode?
Hydrogen (H+)
In the electrolysis of Sodium chloride solution what is produced at the +ve electrode?
Chlorine (Cl-)
Negative electrode (half equation)
2H+ + 2e- -> H2 (small 2)
Positive electrode (hald equation)
2Cl- -> Cl2 (small 2) + 2e- OR 2Cl- - 2e- -> Cl2 (small 2)
Name the uses of chlorine in industry
Production of;
- Bleach
- Plastic
Name the uses of Sodium hydroxide in industry
Strong alkali used in;
- Chemical industry
- Soap
