Chemical Bonding MCQ Quiz in मल्याळम - Objective Question with Answer for Chemical Bonding - സൗജന്യ PDF ഡൗൺലോഡ് ചെയ്യുക

Concept:

Ionic Bond:

• The ionic bond is the electrostatic force of attraction that holds two oppositely charged ions together.
• The complete transfer of one or more electrons from one atom to the other forms a chemical link between two atoms, causing the atoms to acquire their closest inert gas configuration.
• Examples - KCl, AlCl3, NaCl
• When we talk about the stability of ionic compounds we take into account no.of factors like charge and size of cation, size of an anion. 

Explanation:

• As discussed above, the strength of ionic bonding depends on charges and the size of the two ions.
• Higher charges and smaller sizes produce stronger bonds. 
• Since Mg2+ has a small size and high charge for all the actions,
• So its interactions with F -1 will be strongest.
• Also, the electrostatic force of attraction is the maximum

Additional Information

Covalent Bond:

• A covalent connection is created when the electrons from each participating atom are shared equally.
• Shared pair or bonding pair refers to the pair of electrons involved in this sort of bonding.
• Molecular bonds are another name for covalent bonding.
• The atoms will gain stability in their outer shell through the sharing of bonding pairs, analogous to noble gas atoms.
• Examples - CH4, H2O, NH3

Concept:

• Sigma bond is formed by end-to-end overlapping of the orbitals. Whereas, pi-bond is formed by lateral or side-by-side overlapping of p-orbital.

Explanation:

• Each double bond have one pi bond and one sigma bond. Triple bond will have two pi bonds and one sigma bond.
• In the structure given above have C-H, C-C and C=C bonds. Each of this have one sigma bond.
• Only C=C have one pi bond along with sigma bond.
• In the diagram given below, red numbers indicate the pi bonds and black numbers indicate the sigma bonds.

Conclusion:

• Therefore, in the structure given above have 5 π  bonds and 19 σ bonds.
   

Additional Information 

• Given structure is of Naphthalene, which is an aromatic compound. π bonds are not localized at a specific bond, and there is complete conjugation.

• Dotted circle in structure (II) shows that π electrons are distributed over all the 10 carbon atoms.
• Therefore, there is no complete double bond or complete single bond. 

Explanation:-

Types of Bonds in Different Molecules

• Ethane (C₂H₆) (A):
  • Ethane consists of a single bond (σ-bond) between the two carbon atoms.
  • Therefore, there is one σ-bond between the carbon atoms.
  • 
• Ethene (C₂H₄) (B):
  • Ethene consists of a double bond between the two carbon atoms.
  • This includes one σ-bond and one π-bond.
  • 
• Carbon molecule, C₂ (C):
  • The carbon molecule (C₂) has a double bond between the carbon atoms.
  • In some representations, it is considered to have two π-bonds due to the different possible bonding structures of carbon.
  • Diatomic carbon
  • 
• Ethyne (C₂H₂) (D):
  • Ethyne has a triple bond between the two carbon atoms.
  • This includes one σ-bond and two π-bonds.

Based on the above definitions, we can match the items from List I to List II:

• ethane (A) - one σ-bond (III)
• ethene (B) - one σ-bond and one π-bond (IV)
• carbon molecule, C₂ (C) - two π-bonds (II)
• ethyne (D) - one σ-bond and two π-bonds (I)

So the correct match is  A-III, B-IV, C-II, D-I

CONCEPT:

Isostructural Compounds

• Isostructural compounds are those that have the same molecular geometry or structure.
• The geometry of a molecule is determined by the arrangement of the atoms around the central atom, which is influenced by the number of bonding pairs and lone pairs of electrons (VSEPR theory).
• To determine if two compounds are isostructural, compare their molecular geometries and electron configurations.

EXPLANATION:

• a) TiCl₄, SiCl₄: Both have a tetrahedral geometry.
• b) SO42-, CrO2-4^-: Both have different structures; SO42- is trigonal planar, while CrO2-4has a different geometry.
• c) NH₃, NO₃^-: NH₃ is trigonal pyramidal, while NO₃^- is trigonal planar; they are not isostructural.
• d) ClF₃, BCl₃: ClF₃ has a T-shaped geometry, while BCl₃ is trigonal planar; they are not isostructural.

Isostructural compounds are those that have the same structure as well as same hybridisation.

In case (B), the structure of SO2-4 is tetrahedral as it has 4s bonds and zero lone pairs on the central atom. Similarly, CrO2-4 also has 4s bonds and zero lone pairs on the central atom. According to VSEPR, the structures of SO2-4 and CrO2-4 are:

Hence, we can say, SO2-4 and CrO2-4 are isostructural.

In case (A), TiCl4 has 4s bonds and zero lone pairs on the central atom. Hence, it is tetrahedral. Similarly, SiCl4 is also tetrahedral.

Hence, TiCl4 and SiCl4 are also isostructural.

In case (C), NH3 has 3s bonds and 1 lone pair of electrons around nitrogen. Thus, according to VSEPR, NH3 has a pyramidal structure. In NO–3, the nitrogen atom has 3 bonds and no lone pair of electrons. Thus, it is trigonal planar. According to VSEPR, the structures of NH3 and NO–3 are:

Hence, NH3 and NO–3 are not isostructural.

In case (D), ClF3 has 3 s and 2 lone pairs on the central atom. Its structure is distorted T shaped (but geometry is trigonal bipyramidal). BCl3 has 3 s bonds and no lone pair on the B atom. Thus, it is trigonal planar.

Hence, ClF3 and BCl3 are not isostructural.

The correct answer is: 1) A, B

The correct answer is 3.

Key Points

• When two atoms share one electron pair they are said to be joined by a single covalent bond.
• If two atoms share two pairs of electrons, the covalent bond between them is called a double bond.
  • For example, in the carbon dioxide molecule, we have two double bonds between the carbon and oxygen atoms.
  • 
• When combining atoms share three electron pairs as in the case of two nitrogen atoms in the N₂ molecule, a triple bond is formed.
  •  

Important Points

• In many compounds, we have multiple bonds between atoms. The formation of multiple bonds envisages sharing of more than one electron pair between two atoms. 

CONCEPT:

Electron Pair Geometry and Molecular Shape

• The geometry of a molecule is determined by the number of electron pairs (both bonding and non-bonding) around the central atom.
• According to the VSEPR (Valence Shell Electron Pair Repulsion) theory, electron pairs arrange themselves to minimize repulsion.
• A T-shaped molecular geometry typically arises from a trigonal bipyramidal electron domain geometry with three bonding pairs and two non-bonding pairs.

Explanation:-

• Consider the central atom M in the MX₃ molecule with a T-shaped structure:
  • In a T-shaped molecule, there are three bonding pairs of electrons and two non-bonding pairs of electrons around the central atom.
• Thus, the number of non-bonding pairs of electrons on the central atom M is determined as follows:
• Non-bonding pairs = 5 (total pairs) - 3 (bonding pairs) = 2 non-bonding pairs.

Conclusion:-

he number of non-bonding pairs of electrons is 2.

Electron diffraction is used to get the bond parameters of gaseous samples.

Correct option is (b)

Concept:

Intermolecular hydrogen bonding: 

• This type of bonding mainly occurs between two or more same or different molecules when they combine to form a dimer or polymer respectively and leads to a phenomenon known as an association.
• Such a type of hydrogen bonding increases the boiling point of the compound and also its solubility in water. 

Intramolecular hydrogen bonding: 

• This type of bonding occurs within two atoms of the same molecule and leads to a phenomenon known as chelation.
• This type of hydrogen bonding frequently occurs in organic compounds and results in the cyclization (six or five-membered ring) of the molecule. 

Explanation:

• o-nitrophenol has intramolecular hydrogen bonding so it is more volatile.
• So, the statement I is true.
• The lowest melting point of o-isomer is due to intramolecular hydrogen bonding whereas meta and para isomers possess intermolecular hydrogen bonding and thus, they have higher melting points. 
• Thus statement II is false.​

Correct Answer: (3)

The correct answer is White Hydrogen.

Key Points

• White hydrogen: Produced from carbon-free nuclear energy.
• Clean and sustainable: No carbon dioxide emissions during production.
• Generated via electrolysis or thermochemical processes using nuclear power.
• Aiming to decarbonize industries and achieve carbon neutrality. 

Additional Information

• Yellow hydrogen:
  • Produced from natural gas through steam methane reforming, emits carbon dioxide.
• Pink hydrogen:
  • Produced through electrolysis powered by renewable energy sources, clean and sustainable.
• Black hydrogen:
  • Produced from coal gasification or steam methane reforming without carbon capture.

CONCEPT:

Molecular Geometry and Bond Angles

• The geometry of a molecule is determined by the arrangement of atoms around a central atom.
• This arrangement is influenced by the number of bonding pairs and lone pairs of electrons around the central atom.
• Linear molecules have a bond angle of 180°.
• Non-linear (bent) molecules have bond angles that are less than 180°.

EXPLANATION:

• For the given molecules:
  • XeF₂:
    • Has a linear geometry due to the arrangement of 3 lone pairs and 2 bonding pairs around the central Xenon (Xe) atom.
    • 
  • NO₂:
    • Has a bent geometry because of the presence of one lone pair and two bonding pairs around the central Nitrogen (N) atom.
    • 
  • HCN:
    • Has a linear geometry because it consists of a triple bond between Carbon (C) and Nitrogen (N) and a single bond between Hydrogen (H) and Carbon (C).
    • 
  • ClO₂:
    • Has a bent geometry due to the presence of two lone pairs and two bonding pairs around the central Chlorine (Cl) atom.
    • 
  • CO₂:
    • Has a linear geometry because of the double bonds between Carbon (C) and Oxygen (O) atoms, with no lone pairs on the central Carbon atom.
    • 
• Identifying the non-linear molecules:
  • NO₂ and ClO₂ have bent geometries and are non-linear.

Therefore, the non-linear molecule-pair is ClO₂ and NO₂.