Sodium hypochlorite – the chemical compound having a formula NaOCl. It is sodium salt of hypochloric acid. Substance very unstable therefore it is applied in the form of pentahydrate: NaOClx5H2O. Water solution of this salt is known as "a labarrakova water" and has a strong smell of chlorine. It was used (and it continues to be used) as bleach, bactericidal and disinfecting reagent and also in some chemical processes as oxidizer. How it is possible to receive sodium hypochlorite?
It is required to you
- - water solution of hypochlorite of Ca (OCl) 2 calcium;
- - water solution of sodium carbonic (the calcinated soda) Na(СО3)2;
- - cylinder with chlorine;
- - reactionary container with saturated solution of sodium hydroxide;
- - capacity with a large amount of ice, or the ordinary fridge;
- - low-temperature fridge;
- - glass funnel with the filter;
- - thermometer;
- - the plastic hose connected to a cylinder reducer.
Instruction
1. The bleaching properties of chlorine were found at the end of the 18th century when experiments on dissolution of this gas-halogen in water were made. Subsequently chlorine began to be passed through sodium hydroxide, with formation of the solution of NaOCl salt which received the name "labarrakova water" - in honor of the scientist A. Labarrak who offered this way. You can use the same Labarraka method.
2. Place reactionary container in a vessel with ice, lower a tip of a plastic hose in sodium hydroxide solution, unscrew the reducer gate, having adjusted it so that "swirling" of solution of sodium hydroxide was noticeable, but quite weak. Wait several minutes. During this time there will take place reaction: Cl2 + 2NaOH = NaOCl + NaCl + H2O.
3. Wrap the gate, take out a hose from solution, continue cooling (in a vessel with ice or having placed capacity in the ordinary fridge). Wait until temperature of mix is equal 0 degrees. At the same time chloride of sodium will drop out in a deposit in the form of small crystals. Separate this salt by means of a funnel and the paper filter. Place solution in the low-temperature fridge, having established temperature in –40 degrees. Sustain not less than 1 hour, then bring to temperature of-5 degrees. NaOClx5H2O sodium hypochlorite pentahydrate crystals are formed.
4. But it is a way long, besides, it is necessary to use poisonous chlorine. Therefore in laboratory practice it is better to resort to other method. The way is based that reaction will take place up to the end if one of its products leaves a reactionary zone in the form of gas or a deposit. And the formed calcium carbonate – the slightly soluble substance which is dropping out in a deposit: Ca(OCl)2 + Na(CO3)2 = CaCO3 + 2 NaOCl.
5. Mix both solutions. Separate the dropped-out deposit filtering, in solution there will be a sodium hypochlorite.