Tuesday, February 23, 2010

Electrolyte and Non Electrolyte Solutions

Definition
. Electrolyte solution is a solution which can conduct electricity.
. Non electrolyte solution is a solution which can not conduct electricity.


Why electrolyte solution can conduct electricity??
Arrhenius’s theory states “in the electrolyte solution, the dissolved chemical compound (electrolyte substance) is dissociated into ions, even when there is no current flowing through the solution”.
According to Arrhenius’s theory, electrolyte solution can conduct electricity, because in the electrolyte solution there are ions that can move freely. These ions which conduct electric currents.
Electrolyte substances if there are dissolved into water will be dissociated into ions. Meanwhile, for non electrolyte substances will no be dissociated into ions, but they are stay in the form of uncharged molecules. This case causing non electrolyte solution can not conduct electricity. The following are examples of reaction of electrolyte and non electrolyte substance in water.

• Examples of reaction of electrolyte substance in water
NaCl(s) --> Na+(aq) + Cl-(aq)
H2SO4 (l)--> 2H+(aq) + SO42-(aq)
• Examples of reaction of non electrolyte substance in water
C6H12O6(s) --> C6H12O6(aq)
CO(NH2)2(s) --> CO(NH2)2(aq)

On the electrolyte tester. Electrolyte solution shown symptoms such as gas bubbles and glowing lamp, while in non electrolyte solution doesn’t shown that symptoms.

Basic concept of Electrolyte and non electrolyte solutions

solution
non electrolyte solution
Examples:
hydrocarbon compounds
alcohol
ammoniak
electrolyte solution
strong electrolyte solution
Examples:
strong acid
strong base
salt made from strong acid and strong base
weak electrolyte solution
Examples:
weak acid
weak base
salt make from weak acid or weak base

Sample problem

Based on the following data, which solution include in strong electrolyte, weak electrolyte, and non electrolyte solutions.

Solution

Glowing lamp

Bubble gas

A

+

+

B

+

-

C

+

-

D

-

-

E

+

+

Solution

Strong electrolyte solutions: A and E

Weak electrolyte solutions: B and C

Non electrolyte solution: D

Electrolyte intensity

Electrolyte intensity is relate to the number of ions in the solution. Electrolyte intensity is represented by a number called ionization degree (α), which mathematically can be represented by the equation as follows:

α = ni / no

Where α: ionization degree

ni; mole of ionized substance

no: mole of dissolved substance

Sample problem

0,1 mole of HF is dissolved into water, so that in the solution is obtained 0.01 mole of F- ion. Determine the ionization degree of HF solution!


Solution

0.01/0.1= 0.1
because α = 0.1, then the electrolyte substance is weak electrolyte.


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