ACIDS AND BASES

Página 1

ACIDS

produce Hydrogen, H+ ions when dissolved in water

Donate H+ ions- proton donor

When HCL dissolves in water is gives its proton

to water and so therefore is an acid

HCL (g) + H2O (l) -> H3O⁺ (l)

+ Cl⁻

(aq)

Taste sour

conduct electricity

change the colour of indicators

a chemical is usually an acid if it starts with hydrogen- except water

pH less than 7

WEAK ACID

acid which is only partially ionises

produces few H+ ions during ionization

examples: acetic acid, CH3COOH; Carbonic Acid, H2CO3; Phosphoric Acid, H3PO4

STRONG ACID

produces many H+ ions in ionization

completely ionized

HCl, HNO3, H2SO4

BASES

produce hydroxide, OH- ions when dissolved in water

NaOH -> Na⁺ + OH⁻

hydrogen ion acceptors

slippery

bitter

pH greater than 7

WEAK BASE

NH3, CO3, HCO3

STRONG BASE

NaOH, KOH, Na2O, K2O, CaO

ALKALI

base which is soluble in water

gives hydroxide ions in solution

ACID-BASE REACTIONS

Acid + Carbonate -> salt + water + carbon dioxide

Acid + Bicarbonate -> salt + water + carbon dioxide

Active Metal + Acid -> salt + hydrogen

Acid + Hydroxide -> salt + water (neutralisation)

Basic Oxide + Acid-> salt + water

Base + Acid -> salt + water (neutralisation)

IONIZATION IN SOLUTION

occurs when molecular substances form ions in a solution

HCL (aq)

+ H2O (l) -> H3O+ (aq) + Cl- (aq)

Because H2O is a small highly polar molecule it

can remove the proton from the HCL (aq) forming H3O+ and Cl- ions. Therefore

ionization has occurred.

DISSOCIATION

Occur in ionic solids which when dissolved to

water release there ions in the solution

K2CO3 (s)

-> 2K+ + CO3-

Water is highly polar and is able to reduce the

forces of electrostatic attraction which are the ionic bonds between the

oppositely charged ions, to such an extent that the ions are free to move apart

and dissociation has occurred.

ACID, BASE PAIRS

Conjugate base: remainder of the original acid,

after it donates its hydrogen ion

Conjugate acid: particle formed when the

original base gains a hydrogen ion

General Equation: HA + H2O H3O⁺ +

A⁻

Acid + Base

Conjugate acid + Conjugate base

NH3 + H2O NH4⁺ + OH⁻

base + acid ca + cb

HCL + H2O H3O⁺ + Cl⁻

Acid

+ base ca + cb

ACIDS and BASES