Wear lab goggles and gloves. This experiment must be performed in a well-ventilated room or in a fume hood.
Always follow general safety
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During the electrolysis process oxidation reaction of Cl- ions takes place on the anode:
2 Cl- → Cl2 + 2 e-.
Reduction reaction of water takes place on the cathode:
2H2O +2 e- → 2 OH- + H2.
So, chlorine and hydroxide ions are presented together in the solution. They react forming hypochlorite ions
2 OH- + Cl2 → 2 ClO- + H2.
When the obtained solution heats up, hypochlorite turns to chloride and chlorate
3 ClO- → ClO-3 + Cl2.
Produced chlorine reacts with OH- ions again.
When the saturated solution of potassium chloride is added to the solution containing chlorate ions, potassium chlorate is formed. Because the solubility of potassium chlorate is relatively low in comparison with another salts presented in the solution, it is possible to purify potassium chlorate by recrystallization.