Properties of Salts (Svante Arrhenius)
Ionic compounds, or salts, that dissolve in water give solutions that conduct an electric current. Solutions of covalent compounds in water usually do not conduct an electric current. An explanation for this behavior was proposed by Svante Arrhenius while he was a graduate student at the University of Uppsala in Sweden. In 1884 Arrhenius suggested that NaCl dissociates into positively charged Na+ ions and negatively charged Cl- ions when it dissolves in water. Although his professors questioned this theory and only reluctantly granted him his degree, we now know that his theory is correct.
A conductivity apparatus, such as the one shown here, can be used to determine whether a compound can conduct an electric current when it is dissolved in water.
The light bulb inthis conductivity apparatus glows brightly because the appartatus was immersed in an aqueous solution of NaCl. NaCl dissociates into Na+ and Cl- ions when it dissolves in water, which carry the electric current through the solution.
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