HYDROGEN
Experiment 2
Background
• Hydrogen comes from Greek meaning “water producer”
(“hydro” =water and “gennao”=to make).
• Isolated and identified as an element by Cavendish in
1766.
• Named by Antoine Lavoisier.
• One of the most abundant element on the planet.
• Lightest and most abundant element in the universe.
Background
• Hydrogen is the lightest element. It has great affinity for
oxygen and reacts with explosive violence under proper
condition.
• It is capable of taking oxygen from oxide and this affinity is
made use of in the metallurgy in metals.
• Displaced by active metals from dilute acids.
• Some amphoteric metals will displace hydrogen from strong
bases.
Preparation
• Displacement (Lab Activity)
Zn + 4H2SO4  4H2 + ZnSO4
• Electrolysis of Water
2H20 (l)  2H2 (g) + O2 (g)
- Produces the purest form of elemental hydrogen
• Methane Reformation
CH4 (g) + H20 (l)  CO (g) + 3H2 (g)
Preparation
Properties
• Has 3 isotopes: Protium, Deuterium, Tritium
• ¹H: Most common; account 99% of the total hydrogen.
• ²H/D: “Heavy hydrogen”; Separated by fractional distillation of liquid
hydrogen or extended water electrolysis.
• ³H/T: Radioactive. Formed naturally by cosmic ray bombardment.
Properties
• ²H – First created in pure form by the electrolysis of NaOH; Small
amounts of D were found in the electrode.
• ³H – First artificially made by bombarding deuterium
(deuterophosphoric acid) with high-energy deuterons (deuterium
nuclei); Naturally by cosmic ray bombardment of Nitrogen to form n
for the reaction.
Properties
• Atomic Number: 1
• Atomic Weight: 1.0079
• Atomic Radius: 78 pm
• Melting Point: -259.34°C
• Boiling Point: -252.87° C
• Elemental Classification: Non-Metal
• At RT: Colorless, Odorless Diatomic Gas
Activity
• Discuss the relative activity of the following metals when reacted with
HCl in forming hydrogen gas. Write the equation of the reactions.
(15pts)
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Aluminum
Copper
Iron
Tin
Zinc