Дата: 05-01-18 17:25
> В листовката на XTol изрично пише, че
> се разтваря в чешмяна вода.
Distillation and deionization are similar in that both processes remove ionic impurities, but distilled water and deionized water (DI) are not the same and are not interchangeable for many lab purposes.
Distilled water is a type of demineralized water that is purified using distillation. The source water for distillation could be tap water, but spring water is used most often. Usually, the water is boiled and the steam is collected and condensed to yield distilled water.
Most minerals and certain other impurities are left behind, but the purity of the source water is important because some impurities (e.g., volatile organics, mercury) will vaporize along with the water. Distillation removes salts and particulates.
Deionized water is made by running tap water, spring water, or distilled water through an electrically charged resin. Usually, a mixed ion exchange bed with both positive and negative charged resins is used. Cations and anions in the water exchange with H+ and OH- in the resins, producing H2O (water).
Deionized water is reactive, so its properties start to change as soon as it is exposed to air. Deionized water has a pH of 7 when it is delivered, but as soon as it comes into contact with carbon dioxide from the air, the dissolved CO2 reacts to produce H+ and HCO3-, driving the pH closer to 5.6.
Deionization does not remove molecular species (e.g., sugar) or uncharged organic particles (most bacteria, viruses).
Assuming the source water was tap or spring water, distilled water is pure enough for nearly all lab applications. It is used for:
solvent to prepare solution
making high purity water
The purity of deionized water depends on the source water. Deionized water is used when a soft solvent is needed. It is used for:
cooling applications where it's important to avoid depositing minerals
many chemistry experiments involving ionic compounds
washing glassware, especially the final rinse
Честно казано не виждам защо Хтол-а да не може да се разтваря в дестилирана или дейонизирана вода, щом може в чешмяна :)