The law of purity: salt, water and electricity


As part of their 'Elements' magazine, Austrian member company Donau Chemie have prepared a tale that helps to reveal the chemistry going on in every chlor-alkali plant and the eventual fate of these chemicals as they end up in a swimming pool.

Called 'The love story of ions' and written by Joachim Maier, Production Manager of Electrolysis, the original article (in German) can be found on the Donau Chemie website and will help the general public to better understand chlor-alkali chemistry.

A translated version is below.

"Once upon a time, in the depths of the earth, there lived two ions - one sodium and one chloride, that had once been washed up and crystallised from ancient seas. They were happy and content, together for millions of years. One day, they were washed to the surface by a jet of water, suddenly seeing the light of day at the Ebensee lake in Austria. From there they continued their journey to the town of Brückl. “We’re finally out of the darkness!”, they thought, “taking a nice trip... how great!” But their joy didn’t last long because people at the chemical company they arrived at had a different adventure planned for them. The salt was dissolved in water with the sodium remaining on one side of a membrane with some of the water to become caustic soda, whilst the chloride ion, who was even less happy, had to combine with another of its kind to form chlorine gas: two unhappy love affairs. The chlorine was then burnt in a furnace with hydrogen to form hydrochloric acid, meaning it had to languish in a sorry state with its own kind. The sodium had a slightly better time as lye: it went to the sodium hypochlorite facility where it reacted with other chlorine gas. Ultimately, the two ions from our original pair ended up in large, separate storage containers where they awaited their fate!

One summer day, a man came and collected the two separated unhappy ions from the chemical company. He had a little swimming pool at his home and needed both chemicals to treat the water. He first emptied the sodium ion into the pool in the form of an alkaline solution, so he could use his swimming pool for a long-time with his family. The addition of the many alkaline sodium ions, though, meant that he needed something a little more acidic to make the water comfortable to swim in again. He went into his garage where the sad, little chloride ion was whiling away its time, miserable despite the company. The man took the container from the shelf and emptied the chloride ions into the swimming pool in the form of hydrochloric acid. Then came the happy ending for the sodium and chloride ions in our story! They could hardly believe their eyes: they had found each other once more, after all this time. They were very happy, hugging each other and combining again to form salt. They told each another about their adventures whilst they had been apart. From that point on they had a wonderful life of freedom in the sunshine, but above all, back together – bound as sodium chloride!"