= Strong electrolyte
{wiki}
A <strong electrolyte> yields essentially all <ions> from its dissolved substance in the specified <solvent> and conditions. Strength does not specify <concentration>.
For dissolved <sodium chloride> in dilute <water>, one dissolved formula unit supplies one <sodium> <cation> and one <chloride> <anion>. For <hydrogen chloride> in <water>, <ions> instead arise by <proton> transfer to the <solvent>, giving <hydronium> and <chloride>. Thus separating existing <ions> by <dissociation of an ionic compound> and producing <ions> from neutral <molecules> by <ionization> can both give a <strong electrolyte>.<Chemistry 2e by Paul Flowers and others/11.2 Electrolytes>[Chemistry 2e, §11.2, Ionic Electrolytes and Covalent Electrolytes]{ref}
The denominator in “essentially all” is the dissolved inventory. <Solubility> asks how much enters the <chemical solution>; <electrolyte> strength asks what happens to the part that enters. A sparingly soluble <ionic compound> can therefore have an essentially fully dissociated dissolved portion. Undissolved solid does not count as neutral dissolved <chemical species>, and low <electrical conductivity> alone does not establish a <weak electrolyte>.<Chemistry 2e by Paul Flowers and others/11.2 Electrolytes>[Chemistry 2e, §11.2, Ionic Electrolytes, paragraph on sparingly soluble ionic compounds]{ref}
\Image[/electrolyte-strength-species-inventories.png]
{title=<Electrolyte> strength and dissolved <amount of substance> answer different questions}
{description=Original schematic inventories in equal <volume (thermodynamics)> of a specified <solvent>. Each symbol represents the same chosen <amount of substance>, not one literal microscopic sample. A two-unit <strong electrolyte> inventory produces two <cations> and two <anions>; a twenty-unit <weak electrolyte> inventory with a stipulated one-quarter converted fraction produces five of each <ion> and fifteen neutral units. A twenty-unit <nonelectrolyte> inventory remains neutral. The <solvent> and its background <ions> are omitted. These are chosen inventories, not measured material data.}
The diagram's <weak electrolyte> has the smaller converted fraction but more <ions> in the same <volume (thermodynamics)>: ten charged symbols versus four. Even at equal total <ion> <concentrations>, different <ion> <drift velocities> can give different <electrical conductivities>. Strength is useful for predicting dissolved <chemical species> in <chemical equations>; <concentration> and transport properties are additionally needed to predict <electric current>.
An inspected motivating experiment is Harvard Natural Sciences Lecture Demonstrations' <Conductivity of Solutions by Harvard Natural Sciences Lecture Demonstrations>, Setting it Up. Separate labeled beakers hold aqueous <sodium chloride>, <sucrose>, <acetic acid> and <hydrochloric acid> samples specified at $0.10\,\mathrm{mol\,L^{-1}}$, with about $150\,\mathrm{mL}$ in $250\,\mathrm{mL}$ beakers; distilled <water> supplies a blank. Metal <electrodes> enclosed in tubing connect to a lamp. The readout is lamp brightness; the page reports that an ionic <chemical solution> lights the lamp. A separate deionized-<water> rinse station limits carryover between samples.<Conductivity of Solutions by Harvard Natural Sciences Lecture Demonstrations>[Setting it Up, sample list, enclosed electrodes, lamp and rinse station]{ref}
For a controlled interpretation, keep <electrode> spacing and immersed area fixed, compare at the same <temperature>, and recheck the blank after rinsing. These are additional controls: the page supplies no numerical <electrode> geometry, <temperature> or calibration. Brightness supports the presence of mobile <ions>; it cannot alone measure the converted fraction because <concentration>, <ion> mobility and circuit response also matter. Its classification of insoluble compounds as weak should not replace the dissolved-inventory distinction above.<Conductivity of Solutions by Harvard Natural Sciences Lecture Demonstrations>[How it Works and Setting it Up; qualitative readout and unspecified geometry and temperature]{ref}
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