Electrolytes

Electrolytes

Are substances that form positive(+) and

negative (-) ions in water

Conduct an electric current

Electrolytes in the Body

Carry messages send to and from the brain

as electrical signals

Maintain cellular function with the correct

concentrations electrolytes

Strong Electrolytes are 100% ionized

salts H2O 100%ions

NaCl(s) Na+(aq) + Cl-(aq)

H2O

CaBr2(s) Ca2+(aq) + 2Br- (aq)

acids H2O

HCl(g) H3O+(aq) + Cl-(aq)

Weak electrolytes

Most of the solute exists as molecules in solution

Only a few solute particles produce ions

HF + H2O H3O+(aq) + F- (aq)

acid

NH3 + H2O NH4+(aq) + OH- (aq)

base

Classification of electrolytes

1.1. AcidsAcids Binary acids

Ternary acids (oxyacids)

Thioacids

Monoprotic acids

Polyprotic acids

Strong acids

Weak acids

2.2. BasesBases Monovalent

Polyvalent

Strong

Weak

Basic oxides – base anhydrides

Oxides of metals

3.3. SaltsSalts Strong electrolytes!!!

Important Facts

HCl, HNO3 – strong acids

100% dissociation (no equilibrium, no K) HCl H+ + Cl–

0%HCl, 100% H+, 100% Cl–

H+ is a proton, a subatomic particle and does not exist alone in solution

Really H+ + H2O H3O+ (hydronium ion)

HNO3 + H2O NO3– + H3O+

Strong electrolytes weak electrolytes

conc. of ionic form

total concentration =

≤1

Degree of dissociation:

Strong electrolyte: 1

Weak electrolyte: < 0.5

_ +

H

H

H+H

H HH

H H

OO O

O

Cl-

+_

Conductivity of electrolytes

+Na+OH- H O H

H

O

H

H

O

H

H

O

H

Conductivity = 1 ( = resistance)

1 cm

1 cm

V = 1 cm3

= specific conductivity

cc.

NaCl

NH4Cl

H2SO4

Equivalent conductivity:

Conductivity of equivalent amount of electrolyte

= V

V = equivalent dilution in cm3

inf =

v

v = inf =

cc. ( )

400

300

200

100

10 1 10-1 10-2 10-3 10-4 10-5

Strong acid

Weak acid Weak base

Strong base

Salt