Lecture 14 Acids and Bases

Flashcards about Acids and Bases

Arrhenius definition of an acid

A molecular compound that dissociates in water to generate H+/H3O+ ions (and the associated anions)

H3O+ (hydronium ion)

H+

Strong acids

Dissociate 100% in water

Weak acids

Dissociate partially.

The 6 strong acids:

HCl, HBr, HI, HNO3, HClO4, and H2SO4

Arrhenius definition of base

A compound that generates OH– (hydroxide) ions when placed into water

Strong bases

Metal hydroxides (NaOH, KOH, Ca(OH)2, etc)

Weak bases

Generate OH– ions indirectly by reacting with water and removing H+

Brønsted-Lowery acid

A proton (H+) donor

Brønsted-Lowery base

A proton (H+) acceptor

Neutralization reaction

H+ gets transferred from an acid to a base

Amphoteric

Substances that can act as both an acid or a base

Conjugate acid-base pairs

Two substances related to each other by the transfer of a proton

Conjugate Pairs

When an acid loses its H+, it becomes a conjugate base; when a base gains one H+, it becomes a conjugate acid

Acid Strength

The more easily the H–X bond is broken, the more acidic the compound will be.

Acid Strength and Molecular Structure – Binary Acids

Down a group, atoms have larger radii, leads to weaker H–X bonds

Across A Period

Atoms have greater electronegativities, leads to more polar bonds that are easier to break

Acid Strength and Molecular Structure – Oxyacids

Any structural features of Y that can weaken the H–O bond will lead to a stronger acid

Electronegativity of Y

The more electronegative the central atom of an oxyacid, the weaker the H–O bond

Oxygen

The more oxygens bound to the central chlorine atom, the stronger the acid