Table salt - foodstuff which is in each house. All know that salt is easily dissolved in water, but it is how difficult to allocate it back, having returned original strong form? For studying properties of this substance we will make a house experiment.
Properties of table salt
Table or food salt is a vital product for each person. We daily use this product, but seldom we think of its properties.
Table salt in a usual look represents colourless crystals. Salt of natural origin practically always contains in structure a number of useful minerals which give it various shades - from light yellow to brown. This product is very easily dissolved in hot water and it is much worse in cold. Despite full dissolution, it can be allocated easily from water solution. For this purpose it is not necessary to have access to chemical laboratory, it is necessary to make only a small experiment in house conditions.
It is necessary for carrying out an experiment: first, to make solution of salt and to pour solution in a small pan. Secondly, to bring to boiling and to wait when all water completely evaporates. Thirdly to make visual observation as a result of which we will see at the bottom dry crystals of salt. As now it became clear, release of salt from water not such and difficult process. The most ancient way of release of salt from sea water was based on this property. Now salt is extracted from the deposits of rock salt which are usually on places of the dried-up seas.
And whether it is possible to emit salt without heating? For example, having filtered solution via the paper filter. It is unambiguously possible to answer - no. Salt, being dissolved in water, passes into an ionic form - also Cl-breaks up to positively and negatively charged particles of Na +. Ions of salt are evenly distributed among water molecules. The attempt to filter such solution will lead to the fact that the filtrate will contain the same structure, as initial solution as a time of paper filters much more the sizes of ions of salt. Therefore in house conditions the separation of table salt from water filtering is impossible.
Release of salt from solution in the industry
There are industrial ways of release of salts from water. For example, so-called process of desalting of the seas consists in transmission of salty sea water via special membrane filters under high pressure therefore clear fresh water separates, and the damp layer of salt which remained on the filter is in addition uparivat before full drying. Thus, from salty sea water receive two useful products - fresh water and salt for further industrial application.
It is possible to emit salt from solution commercially also vymorazhivaniy: at low temperature impact there is a division of solution into suspension from salt and fresh ice.
From told it is possible to conclude briefly that in house conditions to emit table salt from solution with filtering is impossible, it is possible to reach it only with use of the industrial equipment in special laboratories.