Strong electrolyte

\( \require{mhchem} \)

In chemistry, a strong electrolyte is a solute that completely, or almost completely, ionizes or dissociates in a solution. These ions are good conductors of electric current in the solution.

Originally, a "strong electrolyte" was defined as a chemical compound that, when in aqueous solution, is a good conductor of electricity. With a greater understanding of the properties of ions in solution, its definition was replaced by the present one.

A concentrated solution of this strong electrolyte has a lower vapor pressure than that of pure water at the same temperature. Strong acids, strong bases and soluble ionic salts that are not weak acids or weak bases are strong electrolytes.
Writing reactions

For strong electrolytes, a single reaction arrow shows that the reaction occurs completely in one direction, in contrast to the dissociation of weak electrolytes, which both ionize and re-bond in significant quantities.[1]

\( {\displaystyle {\text{Strong electrolyte}}_{\rm {(aq)}}\longrightarrow {\text{Cation}}_{\rm {(aq)}}^{+}+{\text{Anion}}_{\rm {(aq)}}^{-}} \)

Strong electrolytes conduct electricity only when molten or in aqueous solutions. Strong electrolytes break apart into ions completely.

The stronger an electrolyte the greater the voltage produced when used in a galvanic cell.
Examples

Strong Acids

Perchloric acid HClO₄
Hydriodic acid HI
Hydrobromic acid HBr
Hydrochloric acid HCl
Sulfuric acid H₂SO₄
Nitric acid HNO₃
Chloric acid HClO₃
Bromic acid HBrO₃
Perbromic acid HBrO₄
Periodic acid HIO₄
Fluoroantimonic acid HSbF₆
Magic acid FSO₃HSbF₅
Carborane superacid H(CHB₁₁Cl₁₁)
Fluorosulfuric acid FSO₃H
Triflic acid CF₃SO₃H

Strong Bases

Lithium hydroxide LiOH
Sodium hydroxide NaOH
Potassium hydroxide KOH
Rubidium hydroxide RbOH
Caesium hydroxide CsOH
Calcium hydroxide Ca(OH)₂
Strontium hydroxide Sr(OH)₂
Barium hydroxide Ba(OH)₂
Lithium diisopropylamide (LDA) C₆H₁₄LiN
Lithium diethylamide (LDEA)
Sodium amide NaNH₂
Sodium hydride NaH
Lithium bis(trimethylsilyl)amide ((CH₃)₃Si)₂NLi

Salts

Sodium chloride NaCl
Potassium nitrate KNO₃
Magnesium chloride MgCl₂
Sodium acetate CH₃COONa