Aqueous solution

An aqueous solution refers to the solution of any hydrophilic substance, often of a salt in water.

The fact that a substance is dissolved in water, such as Cl - (aq ) is displayed ( from the Latin aqua ' water) in the sum formula and reaction equations by an appended, subscript " (aq ) ", for dissolved chloride ions. Based on their solubility substances are divided into two groups: hydrophilic ( "water loving ", eg, sodium chloride ) and hydrophobic ( " wassermeidende "; eg oil ) substances; general: ions and strongly polar substances can be released more easily in water than weakly polar substances, as water is a dipole, that is, water molecules have a positive and a negatively charged side. For the same reason can be of non-polar substances only traces dissolved in water; yet even these tracks can already be so large that they become apparent, which can have devastating consequences for oil, for example.

When releasing the Hydratisierungsenergie this is usually free, although other reactions salts, especially the dissolution of the ion lattice, under certain circumstances, the energy balance can bring even into negative territory.

An important characteristic of many aqueous solutions is that they conduct electricity well, while pure water is a very poor conductor.