Chemical Bond and Molecular Structure MCQ Quiz - Objective Question with Answer for Chemical Bond and Molecular Structure - Download Free PDF

The correct answer is Quick lime.

Explanation:

• The chemical formula for quick lime calcium oxide is CaO.
• It reacts with water to form calcium hydroxide.
• The product was left immediately after the calcination of pure limestone.
• It is commonly used in making porcelain and glass and also in preparing bleaching powder
• Limestone forms from the accumulation of shell, coral, algal, and fecal debris that have calcium carbonate in them.
• The chemical composition of chalk is calcium carbonate, with minor amounts of silt and clay.
• Marble (Calcium carbonate) is a biogenic rock and is more compact than chalk.
• As with marble, calcium carbonate is a coarse-crystalline, metamorphic rock that is formed when chalk or limestone is recrystallized under conditions of high temperature and pressure.

The correct answer is They form between non-metals.

Key Points

• Covalent bonds form between non-metals.
• Covalent bonds involve the sharing of electrons, not the loss of electrons. When atoms lose electrons, they form ionic bonds, not covalent bonds. .
• Covalent bonds do not involve the transfer of electrons, which is characteristic of ionic bonds.
• Covalent bonds typically have lower melting and boiling points compared to ionic bonds.
• These bonds can form single, double, or triple bonds, depending on the number of shared electron pairs.

Additional Information

• Ionic Bonds
  • Formed between a metal and a non-metal.
  • Involve the transfer of electrons from one atom to another.
  • Result in the formation of positively and negatively charged ions.
  • Typically have high melting and boiling points.
• Metallic Bonds
  • Formed between metal atoms.
  • Involve a 'sea of electrons' that are free to move around.
  • Responsible for the conductivity and malleability of metals.
• Polar Covalent Bonds
  • A type of covalent bond where electrons are shared unequally.
  • Results in a molecule having a partial positive charge on one end and a partial negative charge on the other.
  • Water (H₂O) is a common example of a molecule with polar covalent bonds.
• Non-Polar Covalent Bonds
  • Electrons are shared equally between atoms.
  • Occurs typically between atoms of the same element.
  • Molecules like O₂ and N₂ are examples of non-polar covalent bonds.

The correct answer is They have weak intermolecular forces.

Key Points

• Covalent compounds are formed by the sharing of electrons between atoms.
• These compounds usually have low melting and boiling points due to the presence of weak intermolecular forces.
• The individual molecules are held together by Van der Waals forces or dipole-dipole interactions, which are much weaker than ionic or metallic bonds.
• As a result, it requires less energy to overcome these forces, leading to lower melting and boiling points.
• Examples of covalent compounds with low melting and boiling points include water (H₂O), methane (CH₄), and carbon dioxide (CO₂).

 Additional Information

• Metallic Bonds
  • Metallic bonds are characterized by a 'sea of electrons' that are free to move around.
  • This type of bonding leads to high melting and boiling points as the bonds are strong and require more energy to break.
• Electrostatic Forces
  • Electrostatic forces are the forces between charged particles, such as ions.
  • In ionic compounds, these forces are very strong, resulting in high melting and boiling points.
• Rigid Lattice Structure
  • A rigid lattice structure is typically found in ionic compounds and some covalent network solids like diamond.
  • This structure contributes to high melting and boiling points due to the strong bonds that hold the lattice together.

The correct answer is Copper Sulphate.

Key Points

• Copper Sulphate, commonly known as Blue Vitriol, is a chemical compound with the formula CuSO₄.
• The compound is widely used as a fungicide, insecticide, and herbicide in agricultural practices.
• Copper Sulphate exists in its pentahydrate form (CuSO₄·5H₂O), which gives it a distinct blue color.
• It is extensively used as a mordant in the textile industry to fix dyes to fibers.
• Other applications include its use in electroplating processes and as a reagent in laboratories.

Additional Information

• Fungicides:
  • Fungicides are chemical or biological agents used to kill or inhibit fungi and fungal spores.
  • Copper-based fungicides like Copper Sulphate are effective against plant diseases such as mildew and blight.
• Mordants:
  • A mordant is a substance used to fix dyes onto fabrics, ensuring color durability and retention.
  • Copper Sulphate is a commonly used mordant in the textile and leather industries.
• Industrial Uses:
  • Copper Sulphate is used in electroplating to coat surfaces with a thin layer of copper.
  • It is also utilized in the preparation of pigments like copper-based blues and greens.
• Environmental Concerns:
  • Excessive use of Copper Sulphate can lead to soil and water contamination.
  • It is toxic to aquatic life if discharged untreated into water bodies.

CONCEPT:

Layers of Carbon Atoms in Graphite

• Graphite is composed of layers of carbon atoms arranged in a hexagonal lattice structure.
• Within each layer, the carbon atoms are bonded through strong covalent bonds.
• However, the layers themselves are held together by weak intermolecular forces known as van der Waals forces.

EXPLANATION:

• The bonding in graphite can be explained as follows:
  • Each carbon atom in a graphite layer forms covalent bonds with three neighboring carbon atoms, creating a planar hexagonal structure.
  • These covalent bonds are strong and responsible for the structural integrity of the individual layers.
  • Between adjacent layers, there are no covalent bonds; instead, the layers are held together by weak van der Waals forces.

• Van der Waals forces are weak intermolecular forces arising due to temporary dipoles in atoms or molecules. These forces allow the layers to slide over each other, giving graphite its characteristic lubricating property.

Therefore, the layers of carbon atoms in graphite are held together by van der Waals forces.

The correct answer is Vermilion.

• Mercury Sulfide is also known as Vermilion.
• It is a chemical compound composed of the chemical elements mercury and sulfur.
• The chemical formula of Mercury sulfide is HgS.
• It is dimorphic with two crystal forms:
  • Red cinnabar
  • Black metacinnabar

Additional Information

• Marsh Gas is the common name of Methane with the formula of CH₄.
• Mohr's Salt is the common name of Ammonium Ferrous Sulphate with the formula of (NH₄)2Fe(SO₄)₂(H₂O)₆.
• Potash Alum is the common name of Potassium Aluminium Sulphate with the formula of KAl(SO₄)₂.

• Amphoteric oxides are the oxides which can react with both acids and base.
• For example, Aluminium oxide (Al₂O₃).
• Aluminium oxide reacts with acids like hydrochloric acid (HCl) and bases like sodium hydroxide (NaOH), to form salt and water.

Al₂O₃ + 6 HCl → 2Al₂Cl₃ + 3H₂O

(Salt)

Al₂O₃ + 2 NaOH → 2 NaAlO₂ + H₂O

(Salt)

The correct answer is Covalent bond.

Important Points

• Graphite has a giant covalent structure in which: each carbon atom is joined to three other carbon atoms by covalent bonds.
  • The bonds which are formed by the medium of mutual sharing of electrons are called covalent bonds.

Additional Information

• When the complete transfer of the valence electron takes place, the bond formed is called the Ionic Bond.
• The partial intermolecular bonding of the lone pair of electrons in the second-row elements like nitrogen, oxygen, or fluorine is called a Hydrogen bond.
• Van der Waals bond is basically a secondary bond which is a weak force of attraction between electrically neutral molecules that collide with or pass very close to each other.

The correct answer is Silver Nitrate.

• Silver Nitrate is an inorganic compound also known as Lunar Caustic with the formula of AgNO₃.
• It is used in photography. It is also less light-sensitive than halides.
• It was once called lunar caustic, since the ancient alchemists, who linked silver with the moon, called silver luna.
• In solid silver nitrate, in a trigonal planar structure, silver ions are three-coordinated.
• Silver nitrate can be treated with nitric acid by reacting with silver, such as silver bullion or silver foil, resulting in silver nitrate, water, and nitrogen oxides. The by-products of the reaction depend on the nitric acid concentration used.

3 Ag + 4 HNO3 (cold and diluted) → 3 AgNO3 + 2 H2O + NO    

Ag + 2 HNO3 (hot and concentrated) → AgNO3 + H2O + NO2

Additional Information

• The common name of Sodium Hydroxide(NaOH) is Caustic Soda.
• The Common name of Hydrochloride Acid(HCl) is Muriatic acid.
• The Common name of Calcium Oxide(CaO) is Lime.

The correct answer is Quick lime.

Explanation:

• The chemical formula for quick lime calcium oxide is CaO.
• It reacts with water to form calcium hydroxide.
• The product was left immediately after the calcination of pure limestone.
• It is commonly used in making porcelain and glass and also in preparing bleaching powder
• Limestone forms from the accumulation of shell, coral, algal, and fecal debris that have calcium carbonate in them.
• The chemical composition of chalk is calcium carbonate, with minor amounts of silt and clay.
• Marble (Calcium carbonate) is a biogenic rock and is more compact than chalk.
• As with marble, calcium carbonate is a coarse-crystalline, metamorphic rock that is formed when chalk or limestone is recrystallized under conditions of high temperature and pressure.

Ethylene has a double bond because it consists of two carbon atoms that are double-bonded to each other. Its chemical formula is C₂H_4.

• Benzene was isolated by Michael Faraday in the year 1825.
• The molecular formula of benzene is C₆H₆, indicates a high degree of unsaturation.
• 
• Benzene has 12 σ and 3 π bonds.

The correct answer is Si.

Important Points

• Catenation is the binding of an element to itself through covalent bonds to form chain or ring molecules.
• Carbon is the most common element that exhibits catenation.
  • It can form long hydrocarbon chains and rings like benzene.
• Please note that the smaller the atom, the stronger the tendency of catenation.
• All the elements of the carbon family or group 4 family exhibit catenation property.
• The carbon family includes carbon (C), silicon (Si), germanium (Ge), tin (Sn), lead (Pb), and flerovium (Fl).
• The ability of an element to catenate is primarily based on the bond energy of the element to itself, which decreases with more diffuse orbitals.
• The bond length decreases across a row in the periodic table and increases down a group.
• The bond energy of S-S is 266 Kj/mol. 
• The bond energy of Si-Si is 340 Kj/mol.
• The bond energy of P-P is 54 Kj/mol.
• The bond energy of N-N is 160 Kj/mol.

Additional Information

• Catenation tendency decreases down the group.
• This happens because the atomic size increases down the group and the strength of the covalent bond decreases.

The correct answer is Option 3, i.e CaSO₄.1/2 H₂O

• The chemical name of the Plaster of Paris is calcium sulphate hemihydrate.
• The chemical formula of the Plaster of Paris is CaSO₄.1/2 H₂O.
• Plaster of Paris is a quick-setting gypsum plaster which is composed of a fine white powder (calcium sulfate hemihydrate), that hardens when moistened and allowed to dry.
• CH3COOH is Acetic Acid.
• (NH4)2SO4 is Ammonium Sulfate.

• Nickel (Ni) is used as a catalyst in the hydrogenation of Vegetable oil.
• Hydrogenation gives us edible fats like Vanaspati.
• Catalyst: It is a substance which increases the rate of a chemical reaction without undergoing any change in its chemical properties.
• Dihydrogen (H₂) is used during the synthesis of ammonia and manufacture of Vanaspati by hydrogenation of polyunsaturated oils.