6.1.1 - Laboratory Activity : Electrolytes and non-electrolytes

Laboratory Activity 6.1.1: Electrolytes and non-electrolytes

Aim: To differentiate electrolytes from non-electrolytes in the molten and aqueous states

Material: » Lead (II) bromide » Lead powder » Potassium iodide » Naphthalene

Apparatus: » Battery » Bulb » Carbon electrodes » Bunsen burner » Tripod stand » Wire gaze » Crucible

Procedure:

	►	(A) Molten state 1. The animation below shows the arrangement and the results of the experiment. 2. The crucible is filled until half full with lead (II) bromide powder. 3. The switch is turned on and the bulb is checked if it is lighted up. 4. Lead (II) bromide powder is heater up until it melts. The switch is turned on again to check of the bulb is lighted up. 5. The experiment is repeated using potassium iodide, lead powder, glucose and naphthalene.
	►	(B) Aqueous state 1. The animation below shows the arrangement and the results of the experiment. 2. 2 – 3 spatula of potassium iodide crystals is added to a beaker containing 250cm³ of water. 3. The solution is stirred until potassium iodide dissolves. 4. The switch is turned on and the bulb is checked if it is lighted up. 5. The experiment is repeated using glucose.

Discussion:

	►	(A) Molten state ○ Lead (II) bromide and potassium iodide can conduct electricity in molten state because they have freely move charged ions. Therefore, they are electrolytes. ○ Lead is a good conductor. ○ Glucose and naphthalene are made of neutral covalent molecules. Ions carrying electrical charges do not exist. Thus, they are non-electrolyte.
	►	(B) Aqueous state ○ Lead (II) bromide and naphthalene are not dissolved in water. Therefore, they are not suitable to use in the investigation of the electrical conductivity in an aqueous solution. ○ Potassium iodide solution conducts electricity as it contains free moving ion in solution. ○ Glucose solution is made up of molecules. Ions carrying electrical charges do not exist. Thus, it cannot conduct electricity.

Conclusion:

►

Electrolyte can conduct electricity in the molten or aqueous states.

↶ 6.1 Properties of Electrolytes and Non-electrolytes

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