SUMMARY: The chapter on Hydrogen in Class 11 Chemistry explores the properties, occurrence, preparation, and uses of hydrogen, as well as its compounds and isotopes. KEY TOPICS: occurrence of hydrogen, isotopes of hydrogen, preparation of hydrogen, properties of hydrogen, hydrides, water and hydrogen peroxide, hydrogen as a fuel, hydrogen economy, hydrogen bonding, uses of hydrogen.
Correct answer: Option 2 — It is a colorless gas at room temperature
Q31 Mark
What is the primary method of preparing hydrogen in the laboratory?
AElectrolysis of water
BCombustion of hydrocarbons
CReaction of acids with metals
DThermal decomposition of water
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Correct answer: Option 3 — Reaction of acids with metals
Q41 Mark
Which of the following compounds contains hydrogen bonding?
AMethane
BWater
CHydrogen chloride
DAmmonia
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Correct answer: Option 2 — Water
Q51 Mark
Which of the following is NOT a use of hydrogen?
AFuel cells
BManufacturing ammonia
CAs a refrigerant
DMaking glass
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Correct answer: Option 4 — Making glass
Q61 Mark
What is the molecular formula of hydrogen peroxide?
AH2O
BH2O2
CH2
DH2O3
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Correct answer: Option 2 — H2O2
Q71 Mark
Which hydride is formed when hydrogen reacts with metals?
AIonic hydrides
BCovalent hydrides
CMetallic hydrides
DNon-metallic hydrides
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Correct answer: Option 1 — Ionic hydrides
Q81 Mark
What is the main component of the hydrogen economy?
AHydrogen fuel cells
BNatural gas
CSolar energy
DNuclear energy
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Correct answer: Option 1 — Hydrogen fuel cells
Q91 Mark
Which isotope of hydrogen has one neutron?
AProtium
BDeuterium
CTritium
DHydrogen-2
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Correct answer: Option 2 — Deuterium
Q101 Mark
Hydrogen is primarily obtained from which of the following sources?
AElectrolysis of salt water
BNatural gas
CCoal gasification
DAll of the above
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Correct answer: Option 4 — All of the above
Q111 Mark
What is the bond angle in a water molecule due to hydrogen bonding?
A90 degrees
B104.5 degrees
C120 degrees
D180 degrees
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Correct answer: Option 2 — 104.5 degrees
Q121 Mark
Which of the following statements about hydrogen is true?
AHydrogen is the lightest element.
BHydrogen is a noble gas.
CHydrogen has a higher boiling point than oxygen.
DHydrogen is a liquid at room temperature.
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Correct answer: Option 1 — Hydrogen is the lightest element.
Q131 Mark
What is the primary reaction involved in the preparation of hydrogen from water?
ACombustion
BDecomposition
CReduction
DElectrolysis
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Correct answer: Option 4 — Electrolysis
Q141 Mark
Which hydride is typically formed with non-metals?
AIonic hydrides
BCovalent hydrides
CMetallic hydrides
DComplex hydrides
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Correct answer: Option 2 — Covalent hydrides
Q151 Mark
What is the role of hydrogen in the Haber process?
AOxidizing agent
BReducing agent
CCatalyst
DInert gas
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Correct answer: Option 2 — Reducing agent
Short Answer Questions10 questions
Q163 Marks
What are the three isotopes of hydrogen and how do they differ from each other?
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The three isotopes of hydrogen are protium (1H), deuterium (2H), and tritium (3H). Protium has no neutrons, deuterium has one neutron, and tritium has two neutrons, resulting in different atomic masses and some differing physical properties.
Q173 Marks
Describe the occurrence of hydrogen in nature. Where is it most commonly found?
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Hydrogen is the most abundant element in the universe, primarily found in stars and gas giant planets. On Earth, it occurs mainly in water (H2O) and organic compounds, rather than in its elemental form.
Q183 Marks
What methods are commonly used for the preparation of hydrogen gas?
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Hydrogen gas can be prepared through several methods, including the electrolysis of water, reaction of acids with metals, and steam reforming of hydrocarbons. Each method has its own applications and efficiency.
Q193 Marks
Explain the significance of hydrogen as a fuel in the context of the hydrogen economy.
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Hydrogen is considered a clean fuel alternative in the hydrogen economy because it produces only water when burned, reducing greenhouse gas emissions. Its use in fuel cells can provide sustainable energy solutions for transportation and power generation.
Q203 Marks
What are hydrides and how are they classified?
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Hydrides are compounds formed between hydrogen and other elements. They are classified into three categories: ionic hydrides, covalent hydrides, and metallic hydrides, based on the type of bonding and the elements involved.
Q213 Marks
Discuss the properties of hydrogen that make it unique compared to other elements.
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Hydrogen is unique due to its low atomic mass, high energy content per unit mass, and its ability to form covalent bonds with many elements. It also exists as a diatomic molecule (H2) under standard conditions, which is significant for its reactivity.
Q223 Marks
What role does hydrogen bonding play in the properties of water?
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Hydrogen bonding in water leads to its high boiling point, surface tension, and solvent properties. These bonds occur between the hydrogen atom of one water molecule and the oxygen atom of another, contributing to water's unique characteristics.
Q233 Marks
Explain how hydrogen peroxide (H2O2) is prepared and its uses.
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Hydrogen peroxide can be prepared by the reaction of barium peroxide with sulfuric acid or through the anthraquinone process. It is used as a bleaching agent, disinfectant, and in various chemical syntheses.
Q243 Marks
What are the main uses of hydrogen in industrial applications?
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Hydrogen is used in various industrial applications, including the production of ammonia for fertilizers, refining petroleum, and as a reducing agent in metallurgical processes. Its versatility makes it crucial in many chemical industries.
Q253 Marks
How does the presence of hydrogen isotopes affect the behavior of water?
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The presence of hydrogen isotopes, such as deuterium and tritium, affects the physical properties of water, including its boiling and freezing points. Deuterated water (D2O) has a higher boiling point than regular water due to the increased mass and stronger hydrogen bonds.
Long Answer Questions6 questions
Q266 Marks
Differentiate between hard water and soft water in tabular form on cause effects and removal.
Q276 Marks
Compare ortho and para hydrogen with the help of a table.
Q286 Marks
Explain the occurrence of hydrogen in the universe and on Earth. What are the primary sources of hydrogen found in nature?
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Hydrogen is the most abundant element in the universe, constituting about 75% of its elemental mass. It is primarily found in stars, including our Sun, where it undergoes nuclear fusion to form helium. On Earth, hydrogen is not found in its free form due to its high reactivity. Instead, it occurs in compounds such as water (H2O) and hydrocarbons. Natural gas, which is primarily methane (CH4), is another significant source of hydrogen. Additionally, hydrogen can be found in organic matter and various minerals.
Q296 Marks
Describe the preparation methods of hydrogen in the laboratory and industry. Provide examples for each method.
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In the laboratory, hydrogen can be prepared by the reaction of metals with acids, such as zinc reacting with hydrochloric acid to produce hydrogen gas. Another method is the electrolysis of water, where an electric current is passed through water to separate it into hydrogen and oxygen. In industry, hydrogen is primarily produced through steam reforming, where natural gas reacts with steam to produce hydrogen and carbon monoxide. Another industrial method is the gasification of coal, which converts coal into gas, yielding hydrogen among other products.
Q306 Marks
Discuss the properties of hydrogen and how they contribute to its applications in various fields.
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Hydrogen is a colorless, odorless, and tasteless gas at room temperature. It has a low density and is highly flammable, which makes it useful as a fuel. Its high energy content per unit mass makes it an attractive alternative energy source. Hydrogen also has a high thermal conductivity and is non-toxic, making it suitable for applications in fuel cells, where it generates electricity through a chemical reaction with oxygen. Additionally, its ability to form strong covalent bonds allows it to participate in various chemical reactions, making it essential in organic chemistry and industrial processes.
Q316 Marks
What are hydrides? Classify them and provide examples of each type.
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Hydrides are compounds formed between hydrogen and other elements. They can be classified into three main categories: ionic hydrides, covalent hydrides, and metallic hydrides. Ionic hydrides, such as sodium hydride (NaH), are formed with highly electropositive metals and contain hydride ions (H-). Covalent hydrides, like water (H2O) and methane (CH4), involve covalent bonding between hydrogen and non-metals. Metallic hydrides, such as palladium hydride (PdH), are formed with transition metals and can absorb hydrogen gas. Each type exhibits distinct properties and reactivity based on the nature of the bonding.
Assertion–Reason Questions8 questions
Q321 Mark
Assertion (A): Hydrogen is the lightest element in the periodic table.
Reason (R): It has an atomic number of 1 and a relative atomic mass of approximately 1.
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Correct answer: Option 1 —
Both A and R are true, and R is the correct explanation of A.
Q331 Mark
Assertion (A): Hydrogen has three isotopes: protium, deuterium, and tritium.
Reason (R): Protium has no neutrons, deuterium has one neutron, and tritium has two neutrons.
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Correct answer: Option 1 —
Both A and R are true, and R is the correct explanation of A.
Q341 Mark
Assertion (A): Hydrogen can be prepared by the electrolysis of water.
Reason (R): Electrolysis involves the decomposition of water into hydrogen and oxygen using an electric current.
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Correct answer: Option 1 —
Both A and R are true, and R is the correct explanation of A.
Q351 Mark
Assertion (A): Hydrogen is a non-metal and exists as a diatomic molecule (H2) under standard conditions.
Reason (R): Diatomic hydrogen is the most stable form of hydrogen at room temperature.
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Correct answer: Option 1 —
Both A and R are true, and R is the correct explanation of A.
Q361 Mark
Assertion (A): Hydrides are compounds formed between hydrogen and metals only.
Reason (R): Hydrides can also form with non-metals, such as in the case of ammonia (NH3).
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Correct answer: Option 3 —
A is true, but R is false.
Q371 Mark
Assertion (A): Water is a compound of hydrogen and oxygen with a bent molecular geometry.
Reason (R): The bent shape is due to the presence of hydrogen bonding between water molecules.
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Correct answer: Option 1 —
Both A and R are true, and R is the correct explanation of A.
Q381 Mark
Assertion (A): Hydrogen can be used as a fuel in fuel cells.
Reason (R): Fuel cells convert hydrogen and oxygen into electricity, with water as the only byproduct.
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Correct answer: Option 1 —
Both A and R are true, and R is the correct explanation of A.
Q391 Mark
Assertion (A): Hydrogen bonding is a weak interaction compared to covalent bonds.
Reason (R): Hydrogen bonds are significantly weaker than covalent bonds but stronger than van der Waals forces.
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Correct answer: Option 1 —
Both A and R are true, and R is the correct explanation of A.
Statement-Based Questions8 questions
Q401 Mark
Statement 1: Hydrogen is the most abundant element in the universe.
Statement 2: Hydrogen has only one stable isotope.
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Correct answer: Option 1 —
Both statements are true.
Q411 Mark
Statement 1: Hydrogen can be prepared by the electrolysis of water.
Statement 2: Hydrogen is a metal at room temperature.
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Correct answer: Option 3 —
Only Statement 2 is true.
Q421 Mark
Statement 1: Hydrides are compounds formed between hydrogen and metals.
Statement 2: Hydrogen bonding is a type of dipole-dipole interaction.
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Correct answer: Option 1 —
Both statements are true.
Q431 Mark
Statement 1: Water is a compound of hydrogen and oxygen.
Statement 2: Hydrogen peroxide contains two hydrogen atoms and two oxygen atoms.
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Correct answer: Option 1 —
Both statements are true.
Q441 Mark
Statement 1: Hydrogen is used as a fuel in fuel cells.
Statement 2: Hydrogen has three isotopes: protium, deuterium, and tritium.
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Correct answer: Option 1 —
Both statements are true.
Q451 Mark
Statement 1: Hydrogen bonding occurs in water molecules.
Statement 2: Hydrogen is less dense than air.
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Correct answer: Option 1 —
Both statements are true.
Q461 Mark
Statement 1: Hydrogen can be produced from natural gas through steam reforming.
Statement 2: Hydrogen is a good conductor of electricity.
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Correct answer: Option 2 —
Only Statement 1 is true.
Q471 Mark
Statement 1: The hydrogen economy refers to the use of hydrogen as a fuel source.
Statement 2: Hydrogen is only found in gaseous form in nature.
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Correct answer: Option 4 —
Both statements are false.
