Electrolytes, Acids, and Bases: Key Concepts and Definitions

Review of Electrolytes and Non-Electrolytes

Introduction to Electrolytes and Non-Electrolytes

Electrolytes and non-electrolytes are important classifications of substances based on their behavior in aqueous solutions. Their ability to conduct electricity depends on whether they dissociate into ions when dissolved in water.

• Electrolytes: Substances that dissociate in water to form ions, allowing the solution to conduct electricity.

• Non-Electrolytes: Substances that do not dissociate in water and thus do not produce ions; their solutions do not conduct electricity.

• Example: Table salt (NaCl) is an electrolyte, while sugar (C12H22O11) is a non-electrolyte.

Strength of Electrolytes

Strong vs. Weak Electrolytes

The strength of an electrolyte depends on the extent to which it dissociates into ions in solution.

• Strong Electrolyte: Completely dissociates into ions in solution. No non-ionized solute remains. Example: Hydrochloric acid (HCl) in water.

• Weak Electrolyte: Partially dissociates into ions; some non-ionized solute remains. Example: Acetic acid (CH3COOH) in water.

• Equations:

  • Strong acid: $\mathrm{HCl} (aq) \rightarrow \mathrm{H}^+ (aq) + \mathrm{Cl}^- (aq)$

  • Weak acid: $\mathrm{CH}_3\mathrm{COOH} (aq) \rightleftharpoons \mathrm{H}^+ (aq) + \mathrm{CH}_3\mathrm{COO}^- (aq)$

Strong Acids and Bases

Strong Acids

There are seven strong acids commonly recognized in general chemistry. These acids dissociate completely in water.

• Hydrochloric acid (HCl)

• Hydrobromic acid (HBr)

• Hydroiodic acid (HI)

• Chloric acid (HClO3)

• Perchloric acid (HClO4)

• Nitric acid (HNO3)

• Sulfuric acid (H2SO4)

• Note: All other acids are considered weak.

Strong Bases

There are eight strong bases, all of which are hydroxides of Group 1 (IA) and Group 2 (IIA) metals.

• Lithium hydroxide (LiOH)

• Sodium hydroxide (NaOH)

• Potassium hydroxide (KOH)

• Rubidium hydroxide (RbOH)

• Cesium hydroxide (CsOH)

• Calcium hydroxide (Ca(OH)2)

• Strontium hydroxide (Sr(OH)2)

• Barium hydroxide (Ba(OH)2)

• Note: All other bases are considered weak.

Remembering the Strong Acids and Bases

Strong bases are all Group IA and IIA metal hydroxides. Strong acids all contain hydrogen paired with monoatomic or polyatomic anions.

• Periodic Table Reference: Group IA and IIA metals form strong bases; strong acids are typically binary or oxyacids with highly electronegative anions.

Definitions of Acids and Bases

Arrhenius Definition

The Arrhenius definition classifies acids and bases based on their behavior in aqueous solutions.

• Acid: Substance which contains H+ and produces H+ ions in aqueous solution.

• Base: Substance which contains OH- and produces OH- ions in aqueous solution.

• Equations:

  • $\mathrm{HCl} (aq) \rightarrow \mathrm{H}^+ (aq) + \mathrm{Cl}^- (aq)$

  • $\mathrm{NaOH} (aq) \rightarrow \mathrm{Na}^+ (aq) + \mathrm{OH}^- (aq)$

Brønsted-Lowry Definition

The Brønsted-Lowry definition expands the concept of acids and bases to include proton transfer reactions.

• Acid: Proton donor

• Base: Proton acceptor

• Proton: H+

• Example: $\mathrm{H}_2\mathrm{O} + \mathrm{NH}_3 \rightleftharpoons \mathrm{NH}_4^+ + \mathrm{OH}^-$

Lewis Definition

The Lewis definition is the broadest, focusing on electron pair interactions.

• Acid: Electron pair acceptor

• Base: Electron pair donor

• Example: $\mathrm{BF}_3 + :\mathrm{NH}_3 \rightarrow \mathrm{F}_3\mathrm{B}-\mathrm{NH}_3$

Additional info: The notes cover foundational concepts in acid-base chemistry, including classification, strength, and definitions, suitable for General Chemistry students.