3.3.3 - Laboratory Activity: Position of Hydrogen in the Reactivity Series

Laboratory Activity 3.3.3: Position of Hydrogen in the Reactivity Series

Aim: To define the position of hydrogen in the reactivity series.
Problem statement: How to define the position of hydrogen in the reactivity series?
Hypothesis: Hydrogen should be position higher than the metal oxide which it able to reduce in the reactivity series.
Variable:

	»	Fixed variable : Hydrogen gas and the reacting condition.
	»	Manipulated variable : Types of metal oxide
	»	Responding variable : Products of reaction

Material: » Zinc » Sulphuric acid » Fused calcium chloride » Lead (II) oxide » Copper (II) oxide » Zinc oxide » Iron (II) oxide

Apparatus: » Flat bottom flask » U-tube » Glass tubing » Bunsen burner » Small crucible

Procedure:

	►	The animation below shows the arrangement of the apparatus and the observation of the experiment.
	►	1. A spatula of dry iron (II) oxide is placed into a small crucible and the apparatus shown above is set up. Safety precautions: ○ The flow of hydrogen is strong and steady to displace the air from the vessel. ○ The gas that flow out from the small hole in the combustion tube to collect. The collected gas is tested with a burning splinter. If no 'pop' sound can be heard, the apparatus is ready to use. (This is to ensure all the air in the combustion tube are expelled) 2. When the apparatus is ready, the excess hydrogen gas that comes out from the end of the combustion tube is ignited. 3. The copper (II) oxide is then heated strongly and hydrogen gas is allowed to flow through until no further changes occurred. 4. The changes are observed and recorded. 5. The experiment is repeated with other metal oxide.

Observation:

►

Mixture Observation Iron (II) oxide The iron (II) oxide glowed to produce solid of grey metal. Water condensed on the cooler part of the apparatus. Lead (II) oxide The lead (II) oxide glowed to produce solid of grey metal. Water condensed on the cooler part of the apparatus. Copper (I) oxide The copper (II) oxide glowed to produce solid of brownish metal. Water condensed on the cooler part of the apparatus Zinc oxide Zinc oxide glowed and no metal is visible. Zinc oxide become yellow when hot but white when cold.

Analysis:

	►	Hydrogen able to reduce iron (II) oxide, copper (II) oxide and lead (II) oxide. ○ FeO(s) + H2(g) → Fe(s) + H2O(l) ○ CuO(s) + H2(g) → Cu(s) + H2O(l) ○ PbO(s) + H2(g) → Pb(s) + H2O(l)
	►	These show that hydrogen is position above iron, copper and lead in the reactivity series.
	►	Hydrogen does not reduces zinc oxide, therefore is should position below zinc in the reactivity series.

Conclusion:

►

Hydrogen is position above iron and below zinc in the reactivity series.

⇲ For exercise(objective and subjective), download for free on Android OS.