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Chapter 9 – Hydrogen

The following Topics and Sub-Topics are covered in this chapter and are available on MSVgo:


You might have heard about the element hydrogen in previous classes. It is the basic and most abundant element among all the elements in the universe. Hydrogen atoms make up over 90% of all the atoms in the universe. Its chemical symbol is H. It is a unique element, and it is of great industrial importance as you will learn further in this topic.

Hydrogen has atomic number one, and it is the first and smallest element in the periodic table. It has only one shell, i.e ‘K’ shell, and has only one electron orbiting its shell. The electronic configuration of hydrogen is 1s.

Hydrogen exhibits dual nature due to its only electron present in the outermost shell. So, it can both gain or lose an electron. It shows alkali metals’ properties that gain an electron to form unipositive ions and show the properties of halogens that lose an electron to form uninegative ions.

Although hydrogen has a resemblance with alkali metals and halogens, it differs from them. Hydrogen is less reactive than halogens, and it doesn’t show metallic properties. Hence, it is best placed separately in the periodic table.

Physical Properties

  1. It is a Colourless and odourless gas.
  2. It is less soluble in water.
  3. It is an inflammable and combustible gas.
  4. It burns with a blue flame.
  5. It is lighter than air.


Chemical Properties

Due to the strong bond enthalpy of the H–H bond, hydrogen is relatively inert at room temperature.

Atomic hydrogen is produced under an electric arc under high temperatures.

Hydrogen combines with almost every element as Its orbit is incomplete with a single electron.

  1.  It completes reactions by any of the three ways: loss of the only electron to give H+, an electron’s gain to form H–, and sharing electrons to form a single covalent bond.

Isotopes have the same atomic number but a different mass number. Three isotopes of hydrogen are: 1H1 (protium), 2H1 (deuterium), and 3H1 (tritium).


Protium is the most common isotope of hydrogen. Its mass number is equal to atomic number = 1 because its nucleus has only a single proton. It has no neutron in its nucleus.


Deuterium is also known as heavy hydrogen. Its mass number is two as it has one proton and one neutron in its nucleus. The nucleus of the deuterium is also called the deuteron.


Among all isotopes of hydrogen, only Tritium is radioactive and emits low energy. It has one proton and two neutrons in its nucleus.

Allotropes are different structural forms of the same element. There are two allotropes of hydrogen: Orthohydrogen and parahydrogen


In orthohydrogen, molecule spins of both the nuclei are parallel


In parahydrogen, molecule spins of both the nuclei are non-parallel

Atomic hydrogen: It is produced as a result of the endothermic reaction of molecular hydrogen. It is very reactive, and it forms hybrids at normal temperature when passed over metals or non-metals except nitrogen. 

Nascent hydrogen: it is a free form of hydrogen which is generated during a chemical reaction. It is a powerful reducing agent.

There are various methods for preparing hydrogen:

Laboratory method

This method usually comprises the reaction of hydrochloric acid, in diluted state, with granulated zinc.

         Zn + 2HCl → ZnCl2 + H2

Hydrogen can also be prepared when zinc reacts with alkali metals.

Commercial method

The commonly used methods are:

  1. Hydrogen can be prepared by electrolysis of acidified water with platinum electrodes.
    2H2O(l) → 2H2(g) + O2(g)
  2. Electrolysis of warm watery barium hydroxide solution with nickel electrodes gives high purity dihydrogen
  3. Electrolysis of brine solution in the preparation of sodium hydroxide and chlorine gives hydrogen as a byproduct Hydrogen is obtained as a byproduct.

Cathode: 2 H+ (aq) + 2 e− → H2 (g)

Anode: 2 Cl− (aq) → Cl2 (g) + 2 e−

Overall reaction: 2 NaCl (or KCl) + 2 H2O → Cl2 + H2 + 2 NaOH (or KOH)

  1. Hydrogen can also be obtained when, in the presence of catalysts, steam reacts on hydrocarbons.

CH4 + H2O ⇌ CO + 3 H2

The mixture of Carbon monoxide and H2 is also called syngas. 

The process of getting ‘syngas’ from coal is called ‘coal gasification’.

Reactions of hydrogen with other elements are as follows:

Hydrogen with halogens: The reaction produces hydrogen halides.

For example hydrogen + chlorine → hydrogen chloride

H2(g) + Cl2(g) → 2HCl(g)

Hydrogen with dioxygen: The reaction gives water.

2H2(g) + O2(g) → 2H2O(l)

Hydrogen with dinitrogen: The reaction results in the formation of ammonia.

N2(g) + 3H2(g) —> 2NH3(g)

Reactions with metals: Hydrogen reacts with metals to form corresponding hybrids.

For example: H2(g) +2M(g) → 2MH(s)

Uses of hydrogen

  1. It is used in the making of vanaspati ghee by way of hydrogenation of the polyunsaturated vegetable oils.
  2. It is used to reduce heavy metal oxides to metals in metallurgical processes.
  3. It serves as a fuel in rockets in space science.
  4. It is used to produce many organic compounds like methanol.
  5. Atomic hydrogen is used in the welding process.
  6. It is used to make metal hybrids
  7. It is used for the synthesis of ammonia, which is used in the manufacture of nitrogenous fertilizers.
  8. It is used for producing the useful chemical hydrogen chloride.

What is hydrogen used for?

Ans. It is used in the production of vanaspati ghee by the hydrogenation of polyunsaturated vegetable oils. It is used to reduce heavy metal oxides to metals in metallurgical processes. It serves as a fuel in rockets in space science. Hydrogen is also used to produce many organic compounds like methanol.

What is hydrogen made up of?

Ans. Hydrogen is an element that exists naturally as a molecule. Each molecule of hydrogen is made up of two hydrogen atoms.

What are 3 interesting facts about hydrogen?

Ans. The interesting facts about hydrogen are

  1.  Hydrogen exhibits dual nature as it has only one electron in its outermost shell. So, it can gain or lose an electron.
  2.  It shows the properties of alkali metals that gain an electron to form unipositive ions and shows the properties of halogens that lose an electron to form uni negative ions.
  3. Although hydrogen has a resemblance to alkali metals and halogens, it differs from them. Hydrogen is less reactive than halogens, and it doesn’t show metallic properties. Hence, it is best placed separately in the periodic table.

Who first discovered hydrogen?

Ans. In 1761, Robert Boyle produced hydrogen gas while experimenting, but it wasn’t until 1766 that Henry Cavendish acknowledged it as a separate component. 

What are the five physical properties of hydrogen?

Ans. The physical properties of hydrogen are:

  1. It is a colourless and odourless gas.
  2. It is less soluble in water.
  3. It is an inflammable and combustible gas.
  4. It burns with a blue flame.
  5. It is lighter than air

Formulae and concepts are critical, and sometimes it’s difficult to understand it by merely reading. Check out videos on MSVgo to understand the concept behind them. MSVgo is a video library based app that explains concepts with examples or explanatory visualizations or animations, which makes learning interesting!

Hydrogen is one of the essential elements in the universe. It is of great importance due to its various uses. In addition to its use as rocket fuel, hydrogen is also being experimented with within the automotive industry.

High School Physics

  • Alternating Current
  • Atoms
  • Communication Systems
  • Current Electricity
  • Dual nature of Radiation and Matter
  • Electric Charges and Fields
  • Electricity
  • Electromagnetic Induction
  • Electromagnetic Waves
  • Electron Beams and Radioactivity
  • Electrons and Photons
  • Electrostatic Potential and Capacitance
  • Fluid Pressure
  • Force and Acceleration
  • Force And Laws Of Motion
  • Gravitation
  • Internal Energy
  • Kinetic Theory
  • Law of motion
  • Light – Reflection And Refraction
  • Magnetic Effects Of Electric Current
  • Magnetism and Matter
  • Management Of Natural Resources
  • Mechanical properties of Fluids
  • Mechanical properties of Solids
  • Motion
  • Motion in a plane
  • Motion in a straight line
  • Moving Charges and Magnetism
  • Nuclear Energy
  • Nuclei
  • Oscillations
  • Our Environment
  • Paths of Heat
  • Physical world
  • Ray optics and optical instruments
  • Semiconductor Devices
  • Semiconductor Electronics: Materials, Devices and Simple Circuits
  • Simple Machines
  • Sound
  • Sources Of Energy
  • Specific and Latent Heats
  • Spherical Mirrors
  • Static Electricity
  • Systems of Particles and Rotational motion
  • Thermal properties of matter
  • Thermodynamics
  • Units and Measurement
  • Vectors, Scalar Quantities and Elementary Calculus
  • Wave Optics
  • Waves
  • Work, Power and Energy

High School Chemistry

  • Acids, Bases and Salts
  • Alcohols, Phenols and Ethers
  • Aldehydes, Ketones and Carboxylic Acids
  • Aliphatic and Aromatic Hydrocarbons
  • Alkyl and Aryl Halides
  • Amines
  • Analytical Chemistry 
  • Atomic Structure
  • Atoms And Molecules
  • Basic concepts of Chemistry
  • Biomolecules
  • Carbon And Its Compounds
  • Carboxylic acids and Acid Derivatives
  • Chemical Bonding and Molecular Structures
  • Chemical Energetics
  • Chemical Equilibria
  • Chemical Kinetics
  • Chemical Reactions And Equations
  • Chemical Reactions and Their Mechanisms
  • Chemistry in Everyday Life
  • Chemistry of p-Block elements
  • Chemistry of Transition and Inner Transition
  • Classification of Elements
  • Coordination Compounds
  • Cyanide, Isocyanide, Nitro compounds and Amines
  • Electrochemistry
  • Electrolysis
  • Elements, Compounds and Mixtures
  • Environmental Chemistry
  • Equilibrium
  • Ethers and Carbonyl compounds
  • Haloalkanes and Haloarenes
  • Hydrocarbons
  • Hydrogen
  • Ideal solutions
  • Introduction to Organic Chemistry
  • Ionic equilibria
  • Matter
  • Matter Around Us
  • Matter In Our Surroundings
  • Metallurgy
  • Metals And Non-Metals
  • Mole Concept and Stoichiometry
  • Natural Resources
  • Organic Chemistry – Basic Principles
  • Periodic Classification of Elements
  • Physical and Chemical Changes
  • Physical and Chemical Properties of Water
  • Polymers
  • Preparation, Properties and Uses of Compounds
  • Principles and Processes of Isolation of Elements
  • Redox Reactions
  • Relative Molecular Mass and Mole
  • States of Matter
  • Structure Of The Atom
  • Study of Compounds
  • Study of Gas Laws
  • Study of Representative Elements
  • Surface Chemistry
  • The d-block and f-block elements
  • The Gaseous State
  • The p-Block Elements
  • The Periodic Table
  • The s-Block Elements
  • The Solid State
  • Thermodynamics

High School Biology

  • Absorption and Movement of Water in Plants
  • Adolescent Issues
  • Anatomy of Flowering Plants
  • Animal Kingdom
  • Bacteria and Fungi-Friends and Foe
  • Biodiversity and Conservation
  • Biofertilizers
  • Biological Classification
  • Biomedical Engineering
  • Biomolecules
  • Biotechnology and its Applications
  • Biotic Community
  • Body Fluids and Circulation
  • Breathing and Exchange of Gases
  • Cell – Unit of Life
  • Cell Cycle and Cell Division
  • Cell Division and Structure of Chromosomes
  • Cell Reproduction
  • Cellular Respiration
  • Chemical Coordination and Integration
  • Circulation
  • Control And Coordination
  • Crop Improvement
  • Digestion and Absorption
  • Diversity In Living Organisms
  • Ecosystem
  • Environmental Issues
  • Excretory Products and their Elimination
  • Flowering Plants
  • Genes and Chromosomes
  • Health and Diseases
  • Health and Its Significance
  • Heredity And Evolution
  • Heredity and Variation
  • How Do Organisms Reproduce?
  • Human Diseases
  • Human Eye And Colourful World
  • Human Health and Disease
  • Human Population
  • Human Reproduction
  • Hygiene
  • Improvement In Food Resources
  • Integumentary System- Skin
  • Kingdom Fungi
  • Kingdom Monera
  • Kingdom Protista
  • Life Processes
  • Locomotion and Movement
  • Microbes in Human Welfare
  • Mineral Nutrition
  • Molecular Basis of Inheritance
  • Morphology of Flowering Plants
  • Neural Control And Coordination
  • Nutrition in Human Beings
  • Organism and Population
  • Photosynthesis
  • Photosynthesis in Higher Plants
  • Plant Growth and Development
  • Plant Kingdom
  • Pollination and Fertilization
  • Pollution; Sources and its effects
  • Principles of Inheritance and Variation
  • Reproduction and Development in Angiosperms
  • Reproduction in Organisms
  • Reproductive Health
  • Respiration in Human Beings
  • Respiration in Plants
  • Respiratory System
  • Sexual Reproduction in Flowering Plants
  • Strategies for Enhancement in Food Production
  • Structural Organisation in Animals
  • Structural Organisation of the Cell
  • The Endocrine System
  • The Fundamental Unit Of Life
  • The Living World
  • The Nervous System and Sense Organs
  • Tissues
  • Transpiration
  • Transport in Plants

High School Math

  • Algebra – Arithmatic Progressions
  • Algebra – Complex Numbers and Quadratic Equations
  • Algebra – Linear Inequalities
  • Algebra – Pair of Linear Equations in Two Variables
  • Algebra – Polynomials
  • Algebra – Principle of Mathematical Induction
  • Algebra – Quadratic Equations
  • Binomial Theorem
  • Calculus – Applications of Derivatives
  • Calculus – Applications of the Integrals
  • Calculus – Continuity and Differentiability
  • Calculus – Differential Equations
  • Calculus – Integrals
  • Geometry – Area
  • Geometry – Circles
  • Geometry – Conic Sections
  • Geometry – Constructions
  • Geometry – Introduction to Euclid’s Geometry
  • Geometry – Three-dimensional Geometry
  • Geometry – Lines and Angles
  • Geometry – Quadrilaterals
  • Geometry – Straight Lines
  • Geometry – Triangles
  • Linear Programming
  • Matrices and Determinants
  • Mensuration – Areas
  • Mensuration – Surface Areas and Volumes
  • Number Systems
  • Number Systems – Real Numbers
  • Permutations and Combinations
  • Probability
  • Sequence and Series
  • Sets and Functions
  • Statistics 
  • Trignometry – Height and Distance
  • Trignometry – Identities
  • Trignometry – Introduction

Middle School Science

  • Acids, Bases And Salts
  • Air and Its Constituents
  • Basic Biology
  • Body Movements
  • Carbon and Its Compounds
  • Cell – Structure And Functions
  • Changes Around Us
  • Chemical Effects Of Electric Current
  • Chemistry in Your Life
  • Coal And Petroleum
  • Combustion And Flame
  • Components Of Food
  • Conservation Of Plants And Animals
  • Crop Production And Management
  • Electric Current And Its Effects
  • Electricity And Circuits
  • Elements and Compounds
  • Fibre To Fabric
  • Food production and management
  • Force And Pressure
  • Forests: Our Lifeline
  • Friction
  • Fun With Magnets
  • Garbage In, Garbage Out
  • Getting To Know Plants
  • Health and Hygiene
  • Heat
  • Hydrogen
  • Life Processes: Nutrition in Animals and Plants
  • Light, Shadows And Reflections
  • Materials: Metals And Non-Metals
  • Matter and Its States
  • Metals and Non-metals
  • Micro Organisms: Friend And Foe
  • Motion And Measurement Of Distances
  • Motion And Time
  • Nutrition In Animals
  • Nutrition In Plants
  • Organization in Living Things
  • Our Environment
  • Physical And Chemical Changes
  • Pollution and conservation
  • Pollution Of Air And Water
  • Reaching The Age Of Adolescence
  • Reproduction In Animals
  • Reproduction In Plants
  • Respiration In Organisms
  • Rocks and Minerals
  • Separation Of Substances
  • Simple Machines
  • Soil
  • Some Natural Phenomena
  • Sorting Materials Into Groups
  • Sound
  • Stars And The Solar System
  • Structure of Atom
  • Synthetic Fibers And Plastics
  • The Living Organisms And Their Surroundings
  • Transfer of Heat
  • Transformation of Substances
  • Transportation In Animals And Plants
  • Universe
  • Waste-water Story
  • Water: A Precious Resource
  • Weather, Climate And Adaptations Of Animals To Climate
  • Winds, Storms And Cyclones

Middle School Math

  • Addition
  • Area and Its Boundary
  • Boxes and Sketches
  • Data Handling
  • Fun With Numbers
  • Heavy and Light
  • How Many
  • Long And Short
  • Mapping
  • Measurement
  • Money
  • Multiplication and Factors
  • Multiply and Divide
  • Numbers
  • Parts and Wholes
  • Pattern Recognition
  • Patterns
  • Play With Patterns
  • Rupees And Paise
  • Shapes And Angles
  • Shapes And Designs
  • Shapes and Space
  • Similarity
  • Smart Charts
  • Squares
  • Subtraction
  • Tables And Shares
  • Tenths and Hundredths
  • Time
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