Electrolysis Flashcards
What is the Acronym for Electrodes?
PANIC (Positive Anode, Negative is Cathode).
How do you test for gas produced by electrolysis?
Damp litmus paper is bleached when in contact with the gas.
What is oxidation?
Loss of electrons, or gaining oxygen.
What is reduction?
Gain of electrons, or losing oxygen
What is an electrolyte?
An ionic compound that is molten or dissolved in water that conducts electricity and is decomposed by it.
What is a cation and what are their properties?
Positively charged ions that move to the negatively charged electrode, the cathode.
What are anions and what are their properties?
Negatively charged ions that move to the negatively charged electrode, the cathode.
What happens to cations at the cathode?
Cations gain electrons from the negatively charged cathode
What happens to anions at the anode?
Anions lose electrons at the positively charged anode
Molten lead bromide, PbBr2(l), is an electrolyte. During electrolysis:
Pb2+ ions gain electrons at the cathode and become Pb atoms.
Br- ions lose electrons at the anode and become Br atoms, which pair up to form Br2 molecules.
So lead forms at the negative electrode and bromine forms at the positive electrode.
What happens to Hydrogen ions during the electrolysis of water?
H+ ions are attracted to the
cathode, gain electrons
and form hydrogen gas.
What happens to Hydroxide ions during the electrolysis of water?
OH- ions are attracted to the
anode, lose electrons and form oxygen gas.
What happens at the cathode with dissolved ionic compounds?
The metal is produced at the cathode if it is less reactive than hydrogen.
Hydrogen is produced at the cathode if the metal is more reactive than hydrogen.
What happens at the anode with dissolved ionic compounds?
For the most common compounds oxygen is produced (from the hydroxide ions).
If halide ions (chloride, bromide or iodide ions) are present, then the negatively charged halide ions lose electrons to form the corresponding non-metal halogen (chlorine, bromine, or iodine).
