Hydrogen and Properties of Dihydrogen MCQ Quiz - Objective Question with Answer for Hydrogen and Properties of Dihydrogen - Download Free PDF

The correct answer is H2.

Key Points

• Hydrogen (H2) is a highly inflammable gas.
• It reacts with oxygen (O2) in the air to form water (H2O) while releasing energy in the form of heat and light.
• Due to its high flammability, hydrogen is used as a fuel in various applications, including rockets and fuel cells.
• In the presence of a spark or flame, hydrogen can combust explosively.

Additional Information

• Nitrogen (N2): It is a non-flammable gas that makes up about 78% of the Earth's atmosphere. It is inert under most conditions.
• Oxygen (O2): While not flammable itself, oxygen supports combustion and can cause other materials to ignite more easily and burn more vigorously.
• Carbon Dioxide (CO2): It is a non-flammable gas that is often used in fire extinguishers due to its ability to suffocate flames.
• Safety Measures: Proper storage and handling are crucial for flammable gases to prevent accidents. This includes using appropriate containers and avoiding sources of ignition.
• Applications: Flammable gases like hydrogen are used in various industrial processes, including welding, cutting, and as energy sources in fuel cells.

• A single hydrogen atom has one proton and one electron.
• One of two or more species of atoms of a chemical element with same atomic number but the different mass number is known as isotopes.  
• Three isotopes of hydrogen are found in nature:
• Protium has no neutron.
• Deuterium has 1 neutron.
• Tritium has 2 neutrons.​

Key Points

• Only tritium (T) is radioactive, because of its very high n/p value,(n/p = 2).
• Tritium is present in meteorites and in the sun
• Tritium, when pure, is a lustrous, white metal.
• Natural Tritium is reported to become very radioactive after bombardment with deuterons. The emitted radiations are mostly positrons and hard gamma rays. 

Hence we can conclude that Tritium is radioactive in nature.

Additional Information

• Deuterium is used to make heavy water(D₂O).
• Heavy water is used in nuclear reactors as a neutron moderator.
• Hydrogen has three naturally occurring isotopes: ₁H¹ (protium), ₁H² (deuterium), and ₁H³ (tritium).
• Other highly unstable nuclei (⁴H to ⁷H) which is not present in nature have been synthesized in the laboratory.​

The correct answer is 1

Key Points

• Hydrogen is the simplest and most abundant element in the universe.
• The hydrogen atom consists of a single proton and a single electron.
• In its neutral state, hydrogen has one electron orbiting its nucleus.
• Hydrogen is represented by the symbol 'H' in the periodic table and has an atomic number of 1.

Important Points

• The mass number is defined as the sum of the total number of protons and neutrons present in the nucleus of an atom. It is a whole number.
• The atomic mass is the average number of protons and neutrons for all-natural isotopes of an element. It can be a decimal number.
• The atomic number is defined as the total number of protons present in the nucleus of an atom.

The correct answer is H+ ions and OH- ions.

Key Points

• In an aqueous solution, acids release H+ ions (hydrogen ions), which are responsible for the acidic properties of the solution.
• Bases, on the other hand, release OH- ions (hydroxide ions) in an aqueous solution, which are responsible for the basic properties.
• The interaction of H+ ions from acids and OH- ions from bases leads to the formation of water (H₂O) and is termed as a neutralization reaction.
• This phenomenon is fundamental to the concept of pH, which measures the acidity or basicity of a solution.
• According to the Brønsted-Lowry theory, acids are proton donors (H+), and bases are proton acceptors (OH-).

Additional Information

• pH Scale:
  • The pH scale ranges from 0 to 14, with 7 being neutral.
  • A pH less than 7 indicates an acidic solution, while a pH greater than 7 indicates a basic solution.
  • The pH scale is logarithmic, meaning each whole number change represents a tenfold change in H+ ion concentration.
• Strong vs. Weak Acids and Bases:
  • Strong acids and bases dissociate completely in water, releasing more H+ or OH- ions, respectively.
  • Weak acids and bases partially dissociate in water, releasing fewer H+ or OH- ions.
• Neutralization Reaction:
  • This is a chemical reaction in which an acid and a base react to form water and a salt.
  • The general equation for a neutralization reaction is: Acid + Base → Salt + Water.
  • Neutralization reactions are exothermic, releasing heat.
• Applications of Acids and Bases:
  • Acids are used in various industries, including food preservation, cleaning agents, and chemical manufacturing.
  • Bases find applications in soap making, cleaning products, and as antacids in medicine.

The correct answer is Ammonia.

Key Points

• Ammonia (NH₃) is a compound of nitrogen and hydrogen.
• When dissolved in water, ammonia forms ammonium hydroxide (NH₄OH).
• Ammonium hydroxide is a weak base and dissociates partially to produce hydroxide ions (OH⁻).
• Hydroxide ions increase the pH of the solution, making it more basic.
• Ammonia is commonly used in cleaning products and fertilizers due to its ability to form hydroxide ions in water.

Additional Information

• Hydroxide Ion (OH⁻)
  • A hydroxide ion is a negatively charged molecule made up of one oxygen bonded to one hydrogen atom.
  • It is a common constituent in many chemical reactions and is a measure of the basicity of a solution.
• pH Scale
  • The pH scale measures the acidity or basicity of a solution.
  • It ranges from 0 to 14, with 7 being neutral, below 7 being acidic, and above 7 being basic.
• Weak Base
  • A weak base is a base that does not ionize fully in an aqueous solution.
  • Ammonium hydroxide is an example of a weak base.
• Common Uses of Ammonia
  • Ammonia is used in household cleaning products, as a refrigerant gas, and in the production of fertilizers.
  • It is also used in the manufacture of plastics, explosives, and other chemicals.

The correct answer is  Hydrogen.
Key Points 

• Hydrogen is the only non-metal placed with alkali metals.
• Hydrogen and alkali metals are placed in group 1 of the periodic table.
• This is so because Hydrogen and alkali metals both have only one electron in their valence shell.
• Alkali metals include Lithium (³Li), Sodium (¹¹Na), Potassium (¹⁹K), Rubidium (³⁷Rb), Caesium (⁵⁵Cs), and Francium (⁸⁷Fr).
• Alkali metals along with Alkaline Earth metals form the s-block elements since the last electron enters the s-orbital.
• Alkali metals are highly reactive, shiny, and soft metals. They readily lose their valence electron to become cations with a +1 charge.
• These react with acids to form salt and hydrogen gas. For eg:
  • 2Na + 2HCl → 2NaCl + H₂

The correct answer is 1.

CONCEPT:

• Isotopes: Isotopes are atoms of the same element that have different numbers of neutrons(mass number) but the same number of protons and electrons(atomic number).
• Deuterium(heavy Hydrogen) and Tritium are isotopes of hydrogen.
   

EXPLANATION:

• Heavy hydrogen(Deuterium) is ₁D² or ₁H².
• Number of neutrons = Mass number(A) - Atomic number(Z)
• For heavy hydrogen, Mass number = 2 and Atomic number = 1.
• Number of neutrons = 1.

Thus, Heavy hydrogen contains one proton and one neutron. 

The correct answer is colourless

CONCEPT:

• Hydrogen is the most abundant gas in the universe. 
• It is the first element in the periodic table.
• The atomic number is 1
• The nucleus of hydrogen contains one proton but no neutron.
• It is lighter than air and insoluble in water.
•  

EXPLANATION:

• Hydrogen is a colourless, odourless gas.

• Hydrogen sulfide is a colorless, flammable, extremely hazardous gas with a “rotten egg” smell.
• Some common names for the gas include sewer gas, stink damp, swamp gas, and manure gas.
• It occurs naturally in crude petroleum, natural gas, and hot springs.
• Insoluble in water; slightly soluble in ethanol, benzene, and ethyl ether.
• In addition, hydrogen sulfide is a highly flammable gas and gas/air mixtures can be explosive.  
• A level of H2S gas at or above 100 ppm is Immediately Dangerous to Life and Health (IDLH).

The correct option is 4 i.e 1 and 3 only.

Key Points

• Hydrogen is the lightest gas and the most abundant element in the universe.
• Hydrogen can be corrosive at elevated temperatures and pressures. Hence, statement II is incorrect.
• Deuterium and Protium are the isotopes of the hydrogen
• Deuterium is another name for heavy hydrogen.
• It contains one proton and one neutron.
• Protium has no neutrons in the nucleus.

The correct answer is hydrogen.

Important Points 

• Alkali Metals:
  • Alkali metals react vigorously with cold water resulting in the displacement of hydrogen.
  • Hydrogen (H), lithium (Li), sodium (Na), potassium (K), rubidium (Rb), caesium (Cs), and francium (Fr) are called alkali metals.
  • Alkali metals are soft, shiny, low-melting, highly reactive metals, which tarnish when exposed to air. 
  • Alkali metals are very reactive, they are found in their elemental form in nature, and are usually found as ionic compounds (except for hydrogen).
  • They have only one valence electron in the highest-energy orbitals (ns1). 
  • They have low melting points.
  • These elements react vigorously with water and produce metal hydroxide, hydrogen gas, and heat. 

• It contains a mixture of deuterium oxide and tritium oxide in a space surrounding an ordinary hydrogen bomb.
• The first step of the reaction is endothermic i.e. reaction between deuterium oxide and tritium oxide is initiated by the energy obtained from the explosion of the atom bomb.
• The second step of the reaction is exothermic i.e. energy evolving.
• Nuclear Fusion
• The process which involves the fusion of two or lighter nuclei to give heavier nuclei is called nuclear fusion.
• It occurs only at extremely high temperatures (>10⁶K), so also called thermonuclear reactions.
• It is used in a hydrogen bomb.
• The energy of the sun and stars is also a result of a series of nuclear fusion reactions.

Additional Information 

• It is the phenomenon of artificial transmutation in which a heavy nucleus splits up into two or lighter nuclei of nearly comparable mass with the release of a tremendous amount of energy.
• It was discovered by two German scientists Otto Hahn and Fritz Strassmann in 1939.

The correct answer is H2.

Key Points

• Hydrogen gas is inflammable.
• The inflammable substances have very low ignition temperature and such substances easily catch fire.
• The ignition temperature is the lowest temperature at which a combustible substance when heated takes fire in the air.
• It is the diatomic hydrogen gas which is extremely flammable.
• Please note that many flammable substances have to be at a high concentration in order to actually combust or catch fire. However, in the case of hydrogen gas, it would combust at concentrations as low as 4 percent up to 75 percent.
• It has been seen in hydrogen that it would combust when exposed to sunlight and even very minor increases in temperature can cause the combustion because of its highly reactive nature.
• The reaction for this combustion is:-
  • 2H₂(Gas) + O₂ (Gas) = 2H₂O (Liquid) + 572 kJ energy (286kJ/mol H₂)
• Acetylene, ammonia, hydrogen, propane, propylene, and methane are all flammable gases, also known as fuel gases.

Mistake Points

• Flammable and inflammable do not mean the same thing. If something is flammable it means it can be set fire to, such as a piece of wood. However, inflammable means that a substance is capable of bursting into flames without the need for any ignition.
• Opposite of flammable is non-flammable.

The correct answer is tritium.

• The most stable radioactive isotope is tritium, with a half-life of 12.32 years. 

Key Points

• Hydrogen is the first element in the periodic table and has the atomic number one.
  • Those elements which have the same atomic number but a different mass number are called isotopes.
  • There are three isotopes of hydrogen namely, protium 1H1, deuterium 1H2 or D, and lastly tritium 1H3 or T.
  • The isotopes are different because of the different number of neutrons present in them.
  • In protium, there is no presence of neutrons, whereas in deuterium we have one neutron and in tritium, we have two neutrons.
  • The most prominent form of hydrogen is protium, 0.0156% of hydrogen is present on the earth’s surface as deuterium.
  • In tritium, the concentration is one atom per 1018 atoms of protium. Out of these three isotopes of hydrogen.

Important Points

• Out of these three isotopes of hydrogen, only tritium is radioactive in nature which emits low energy b particles.
• As the electronic configuration of isotopes is the same, they all have similar chemical properties. But they have a difference in their rates of reaction, this happens because of the different bond disassociation enthalpies.
• They have different physical properties because of the large variations in mass.
• The occurrence of hydrogen on earth is difficult due to its light nature.
• In combined it forms 15.4% of hydrogen that occurs in the earth’s crust and oceans.
• Hydrogen also occurs in plant and animal tissues, hydrocarbons, proteins, hydrides, and many other compounds.
• In the universe, hydrogen is the most abundant element (70% of the total mass) and it is also the principal element of the solar atmosphere.
• Even the huge planets such as Jupiter and Saturn mainly consist of hydrogen.

Additional Information 

• Protium ( ¹H )
  • It is one of the common isotopes of hydrogen.
  • It is plenty in nature with an abundance of 99.98%.
  • One of the reasons for this is that the nucleus of this isotope consists of a single proton and this proton at no time, has been reported to be decayed.
  • The mass of protium is 1.007825 amu.
  • Hydrogen generally combines with other atoms in compounds and is usually found in H₂ ( diatomic hydrogen gas).
• Deuterium ( ²H)
  • It comprises 1 proton and 1 neutron in its nucleus.
  • The nucleus of hydrogen 2 is termed deuteron.
  • It is not radioactive.
  • Its compounds are used in chemical analysis and solvents for hydrogen 1. 
  • Heavy water is enriched with molecules consisting of deuterium instead of protium.
  • It is used as a coolant and a neutron moderator.
  • Hydrogen 2 is also used as a fuel in nuclear fusion (commercial).
  • It occurs naturally as deuterium gas.
• Tritium ( ³H )
  • It comprises 2 neutrons and 1 proton in its nucleus.
  • Small traces of hydrogen 3 or tritium occurs in nature due to the synergy of cosmic rays with atmospheric gases.
  • They are also released in a small amount at the time of nuclear weapons tests.
  • It is radioactive, it decays into helium 3 through beta decay.
  • Hydrogen 3 as an atomic mass of 3.0160492 u.

The correct answer is Colourless.

Explanation:

• Hydrogen is the most abundant gas in the universe.
• The chemical element hydrogen has the symbol H and the atomic number 1.
• It is the very first element in the periodic table.
• The hydrogen nucleus contains one proton but no neutron.
• It is insoluble in water and lighter than the air.
• In nature, hydrogen gas is colourless, odourless, non-toxic, and tasteless.
• It is a combustible gas, but it does not support combustion

Thus, the colour of the hydrogen gas is colourless.