Electrolysis of brine

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Offline rainy872000

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Electrolysis of brine
« on: 29/11/2005 06:19:12 »
Hello,
In my chemistry exam paper, there was a question abt the electrolysis of brine... it asks what is one important compound/substance that is formed in the aqueous solution and suggest how it is formed by electrolysis? Is it accurate to put sodium chlorate? i think most of my friends put sodium hydroxide...
 

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Offline chris

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Re: Electrolysis of brine
« Reply #1 on: 29/11/2005 15:05:47 »
When you electrolyse brine - sodium chloride solution - at the anode (positive electrode) 2 chloride ions (Cl-) surrender 2 electrons and bond covalently to form a molecule of Cl2 (chlorine gas) :

2Cl- -> 2e- + Cl2 (g)

At the cathode (negative electrode) 2 hydrogen ions (H+) pick up 2 electrons and combine covalently to form a molecule of hydrogen gas :

2H+ + 2e- -> H2 (g)

The removal of H+ ions from the water leaves sodium (Na+) ions and hydroxyl (OH-) ions in solution, producing a basic solution (alkaline) of sodium hydroxide.

Chris

"I never forget a face, but in your case I'll make an exception"
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I never forget a face, but in your case I'll make an exception - Groucho Marx