Electrolysis Experiment 2: Potassium Iodide Flashcards
What colour is phenolphthalein in a base?
Pink
Explain how the experiment is carried out
Water and potassium iodide are mixed in a petri dish. An electrode is placed on both sides of the solution. Phenolphthalein is added to the solution.
What ions are formed from the potassium iodide solution?
K+ and I-
What ions are formed from the dissociation of water?
H+ and OH-
State whether oxidation or reduction takes place at the anode or cathode?
Anode- Oxidation
Cathode- Reduction
What electrode are I- and OH- attracted to? and state the charge of this electrode.
The anode and it has a positive charge
What happens to the iodide ions at the anode?
It’s converted into iodine
Give the chemical equation for what takes place at the anode
_ _
2I + 2e -> I2
What electrode are K+ and H+ attracted to? and state the charge of this electrode.
The Cathode and it has a negative charge
What happens to hydrogen ions at the cathode?
They are converted to hydrogen
Give the chemical equation for what takes place at the cathode
+ _
2H + 2e -> H2
What is left around the cathode in excess and state whether in is an acid or a base.
Oh- is a base
What does the OH- do to phenolphthalein?
Turns it from clear to pink
