Laboratory and Industrial Methods for Preparation of Hydrogen Gas
Preparation of Hydrogen and its uses is essential in chemistry and helps students understand various practical and theoretical applications related to this topic.
What is Preparation of Hydrogen and Its Uses in Chemistry?
Preparation of hydrogen in chemistry refers to the various methods used to make hydrogen gas (H2), the most abundant element in the universe. Hydrogen is part of topics like reactivity of elements, inorganic chemistry, and fuel technology, making it an important concept for foundational chemistry studies.
Molecular Formula and Composition
The molecular formula of hydrogen gas is H2. It is a diatomic molecule made of two hydrogen atoms, each with one proton and one electron.
Hydrogen falls under the category of nonmetals and is structurally the simplest element found in the periodic table.
Preparation and Synthesis Methods
Hydrogen can be prepared both in laboratories and on an industrial scale. Here are the most common methods for preparation of hydrogen gas:
- Laboratory Preparation (Metal + Acid): Hydrogen is produced when dilute acids (like HCl or H2SO4) react with metals such as zinc.
Zn + 2HCl → ZnCl2 + H2↑ - Lab Preparation (Metal + Alkali): Certain metals like zinc also react with strong alkalis (e.g., NaOH) to release hydrogen.
Zn + 2NaOH → Na2ZnO2 + H2↑ - Electrolysis of Water (Industrial): Water can be split into hydrogen and oxygen by passing an electric current.
2H2O(l) → 2H2(g) + O2(g) - Steam Reforming of Methane (Industrial): Natural gas reacts with steam over a catalyst to produce hydrogen.
CH4 + H2O → CO + 3H2 - Bosch Process (Coke + Steam): Coke (carbon) reacts with steam at high temperature to yield hydrogen.
C + H2O → CO + H2
For laboratory preparation, granulated zinc and dilute acid are commonly used because the reaction is safer and easier to control compared to more reactive metals such as sodium.
Physical Properties of Preparation Of Hydrogen And Its Uses
Hydrogen is a colorless, odorless, and tasteless gas. It is lighter than air and is the least dense of all gases. Hydrogen is insoluble in water but very slightly soluble, and it is highly flammable—burning with a pale blue flame to form water.
Chemical Properties and Reactions
Hydrogen is not very reactive at room temperature due to the stability of the H2 molecule. However, it shows the following reactions:
- Combustion: Hydrogen burns in air or oxygen to give water.
2H2 + O2 → 2H2O - Reduction: Hydrogen reduces metal oxides to metals.
CuO + H2 → Cu + H2O - Reaction with Halogens: Forms hydrogen halides.
H2 + Cl2 → 2HCl - Reaction with Nitrogen: Produces ammonia in the Haber process.
N2 + 3H2 → 2NH3
Frequent Related Errors
- Confusing hydrogen’s lightness with helium in balloons.
- Not removing air properly before collecting hydrogen, leading to explosions.
- Using sodium or potassium instead of zinc, causing dangerous laboratory reactions.
- Mixing up laboratory and industrial methods for hydrogen generation.
Uses of Preparation Of Hydrogen And Its Uses in Real Life
Hydrogen gas has various important uses:
- Manufacture of Ammonia: Used in fertilizers.
- Hydrogenation of Oils: Converts vegetable oils to fats.
- Rocket Fuel: Used in combination with oxygen.
- Fuel Cells: Clean source of electric power.
- Metal Extraction: Reduces ores to pure metals.
Hydrogen is also found in hydrogen fuel technology and is used in hydrogenation of oils for making margarine and vanaspati.
Relation with Other Chemistry Concepts
Preparation of hydrogen is linked with extraction of metals, oxidation-reduction reactions, and acid-base chemistry. It forms the foundation for studying electrolysis of water and industrial chemical manufacturing.
Step-by-Step Reaction Example
- Reacting zinc with dilute hydrochloric acid produces hydrogen gas.
Zn + 2HCl → ZnCl2 + H2↑ - Set up the reaction in a flask with granulated zinc.
Add dilute HCl slowly and collect hydrogen by downward displacement of water. - Hydrogen gas is captured in an inverted test tube.
Hold a burning splint at the mouth; a 'pop' sound confirms H2.
Lab or Experimental Tips
Always use granulated zinc for smooth hydrogen evolution in labs. Do not use sodium or potassium for safety reasons. Purge air from the apparatus before collecting hydrogen to avoid explosive mixtures—a tip often highlighted in Vedantu classes for safe practical work.
Try This Yourself
- Name the most common industrial method for hydrogen preparation.
- Write the balanced equation for lab preparation of hydrogen using zinc and sulfuric acid.
- Give two everyday uses for hydrogen gas.
- Describe how you would test for hydrogen gas in a laboratory.
Final Wrap-Up
We explored preparation of hydrogen and its uses—covering how H2 is made in the lab and industry, key physical and chemical properties, and its wide-ranging applications in daily life and industry. For stepwise explanations, safe lab techniques, and extra questions, join live classes and download summary notes at Vedantu.
FAQs on Preparation of Hydrogen and Its Main Uses
1. What is the preparation of hydrogen gas?
Hydrogen gas can be prepared by several methods:
Laboratory methods:
• Reacting dilute acids (like sulphuric acid) with reactive metals (such as zinc):
Zn + H2SO4 → ZnSO4 + H2↑
• Reacting alkalis with metals like aluminium.
Industrial methods:
• Electrolysis of water: Splitting water into hydrogen and oxygen gases.
• Steam reforming of methane.
• Bosch process using coke and steam.
2. What are the main uses of hydrogen gas?
Hydrogen gas is widely used due to its unique properties. Main uses include:
• Ammonia synthesis (Haber process)
• Hydrogenation of oils
• Rocket fuel
• Fuel cells for clean energy
• Welding (oxy-hydrogen torch)
• Reducing agent in metallurgy
3. How is hydrogen prepared from water?
Hydrogen can be prepared from water by the process of electrolysis.
• In electrolysis, an electric current splits water (H2O) into hydrogen (H2) and oxygen (O2) gases.
• The reaction: 2H2O(l) → 2H2(g) + O2(g)
4. Which metal is commonly used for the laboratory preparation of hydrogen?
Zinc metal is commonly used for laboratory preparation of hydrogen.
• Zinc reacts with dilute sulphuric acid to produce hydrogen gas.
• Equation: Zn + H2SO4 → ZnSO4 + H2↑
5. What are the main physical properties of hydrogen gas?
Hydrogen gas has these physical properties:
• Colorless, odorless, and tasteless gas
• Lightest element (very low density)
• Slightly soluble in water
• Insoluble in most solvents
• Non-toxic but not breathable
6. What are key chemical properties of hydrogen gas?
Hydrogen gas shows important chemical properties:
• Combines explosively with oxygen to form water
• Reacts with chlorine to form HCl
• Reduces metal oxides to metals
• Acts as a reducing agent
• Forms covalent bonds
7. Why is hydrogen considered a clean fuel?
Hydrogen is called a clean fuel because:
• It produces only water upon combustion, with no carbon emissions
• Has a high energy content per unit mass
• Used in fuel cells for sustainable energy solutions
8. What safety precautions should be taken when preparing hydrogen in the laboratory?
Key safety precautions:
• Always perform reactions in a well-ventilated area.
• Avoid open flames – hydrogen is highly flammable.
• Use dilute acids and appropriate metals (zinc is preferred).
• Collect gas by downward displacement of water or in dry containers only after initial air has been removed.
9. How is hydrogen gas tested or identified in a laboratory?
Hydrogen gas can be tested by:
• Bringing a burning splint near the mouth of the test tube – it produces a characteristic ‘pop’ sound due to rapid combustion.
• The pop confirms the presence of hydrogen.
10. Can hydrogen gas be used for breathing?
No, hydrogen gas cannot be used for breathing.
• Hydrogen is not breathable by humans and has no nutritive or respiratory value.
• Inhalation can cause suffocation due to displacement of oxygen.
11. Why are sodium and potassium not used for hydrogen production in the laboratory?
Sodium and potassium react dangerously with water or acids.
• They cause violent, explosive reactions.
• This makes them unsafe for controlled laboratory hydrogen preparation; zinc and iron are preferred instead.
12. What is one important use of hydrogen in the chemical industry?
Hydrogen is essential in the Haber process for ammonia synthesis.
• Ammonia (NH3) is crucial for fertilizers.
• Equation: N2 + 3H2 ⇌ 2NH3
