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Hydrogen

The lightest and simplest element — how hydrogen was discovered, how it is prepared in the laboratory and industry, and how it reacts and is used.

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What this chapter covers

  1. Introduction to Hydrogen

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    • Discovery of HydrogenNamed 'water former' by Lavoisier.
    • OccurrenceAbout 1% of the Earth's crust.
    • Importance of Hydrogen

  2. Preparation of Hydrogen

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    • General Methods of PreparationReactive metals with water or steam.
    • Laboratory Preparation of HydrogenGranulated zinc with dilute sulphuric acid.

  3. Properties of Hydrogen

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    • Physical PropertiesColourless, odourless; lightest of all gases.
    • Chemical PropertiesNeutral; burns with pale, non-luminous flame.
    • Reaction of Hydrogen with Non-metalsForms HCl and NH₃ with non-metals.
    • Reaction of Hydrogen with MetalsHeated sodium, potassium form metal hydrides.
    • Reaction of Hydrogen with Metal OxidesReduces heated metal oxides to metal.
    • Hydrogen as a Reducing AgentRemoves oxygen; itself gets oxidised.

  4. Industrial Preparation of Hydrogen

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    • Bosch ProcessWater gas, then shift with steam.
    • Electrolysis of Acidulated WaterElectric current splits slightly acidified water.

  5. Uses of Hydrogen

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    • Industrial FuelHigh heat of combustion, eco-friendly.
    • Synthesis of CompoundsUsed to make ammonia and HCl.
    • Oil Coal HydrogenationOils become ghee; coal becomes liquid.
    • Oxy-hydrogen Torch2500°C flame for cutting, welding.
    • MetallurgyExtracts copper, iron, lead by reduction.

Try a sample question

Where does free (uncombined) hydrogen mainly occur?

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