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.
Strong electrolyte ( a q ) ⟶ Cation ( a q ) + + Anion ( a q ) − {\displaystyle {\text{Strong electrolyte}}_{\rm {(aq)}}\longrightarrow {\text{Cation}}_{\rm {(aq)}}^{+}+{\text{Anion}}_{\rm {(aq)}}^{-}}
Strong electrolytes conduct electricity only in aqueous solutions, or in molten salt, and ionic liquid. Strong electrolytes break apart into ions completely. The strength of an electrolyte does not affect the open circuit voltage produced by a galvanic cell. But when electric current flows, stronger electrolytes result in smaller voltage losses through the electrolyte and therefore higher cell voltage.
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
See also Aqueous solution Dissociation constant Electrolysis Electrolyte Ionic liquid Molten salt Supporting electrolyte (background electrolyte)
References