KCl, also referred to as potassium chloride, is soluble in water. The polar property of water allows ionic substances to dissolve in water, according to Everything Science.

When an ionic compound is dissolved in water, the positive ion of the compound is drawn to the negative pole of water, whereas the negative ion is drawn to the positive pole. In water, KCl dissociates into K+ and Cl- ions by dissolution and dissociation.

According to ScienceGeek.com, at temperatures above 30 degrees Celsius, KCl is more soluble than table salt, NaCl. According to KnowsWhy.com, the ability of KCl to dissolve in water makes it beneficial in the production of fertiliser because plants require potassium for growth. KCl also dissolves in alcohol and other alkalis, in addition to water.