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This change in structure is related to the lower density of the liquid phase (1.78 g/cm 3) versus solid aluminium trichloride (2.48 g/cm 3). Al 2 Cl 6 dimers are also found in the vapour phase. At higher temperatures, the Al 2 Cl 6 dimers dissociate into trigonal planar AlCl 3 monomer, which is structurally analogous to BF 3.
Most of the solute does not dissociate in a weak electrolyte, whereas in a strong electrolyte a higher ratio of solute dissociates to form free ions. A weak electrolyte is a substance whose solute exists in solution mostly in the form of molecules (which are said to be "undissociated"), with only a small fraction in the form of ions.
Liquid nitrogen. Liquefaction of gases is physical conversion of a gas into a liquid state (condensation). The liquefaction of gases is a complicated process that uses various compressions and expansions to achieve high pressures and very low temperatures, using, for example, turboexpanders.
It occurs both naturally and artificially. As an example of the latter, a "major commercial application of liquefaction is the liquefaction of air to allow separation of the constituents, such as oxygen, nitrogen, and the noble gases." [4] Another is the conversion of solid coal into a liquid form usable as a substitute for liquid fuels. [5]
The noble gases do not react with water, but their solubility in water increases when going down the group. Argon atoms in water appear to have a first hydration shell composed of 16±2 water molecules at a distance of 280–540 pm, and a weaker second hydration shell is found out to 800 pm. Similar hydration spheres have been found for krypton ...
The boiling point is the temperature at which there is equilibrium between liquid and gas phases. At the boiling point, the number of gas molecules condensing to liquid equals the number of liquid molecules evaporating to gas. Adding a solute dilutes the concentration of the liquid molecules and reduces the rate of evaporation.
A common kind of hydrolysis occurs when a salt of a weak acid or weak base (or both) is dissolved in water. Water spontaneously ionizes into hydroxide anions and hydronium cations. The salt also dissociates into its constituent anions and cations. For example, sodium acetate dissociates in water into sodium and acetate ions.
They catch fire spontaneously in air and react with water, thus necessitating precautions when handling them. They often form dimers, unlike their boron analogues, but this tendency diminishes for branched-chain alkyls (e.g. Pr i , Bu i , Me 3 CCH 2 ); for example, triisobutylaluminium exists as an equilibrium mixture of the monomer and dimer.