Chemistry

Chemical Bonding and Molecular Structure

1,277 Questions

This section tests your knowledge of chemical bonding, molecular structure, and hybridization. It covers ionic and covalent bonds, octet rule exceptions, and molecular geometry. These chemistry questions are common in various competitive entrance examinations.

Ionic and covalent bondsHybridisation of elementsOctet rule exceptionsMolecular geometryIntermolecular forces

Chemical Bonding and Molecular Structure Questions

Multiple choice chemistry the world of carbon organic compounds allotropes of carbon versatile nature of carbon

In diamond, the bonding between carbon atoms is :

  1. co-ordinate

  2. ionic

  3. electrostatic

  4. covalent
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

In diamond, each carbon atom is covalently bonded to four other carbon atoms. A lot of energy is needed to separate the atoms in diamond. 


This is because covalent bonds are strong and diamond contains many covalent bonds. 

Hence, the correct option is $D$

Multiple choice chemistry organic chemistry : some basic principles and techniques methods of purification of organic compounds methods of purification - organic compounds biochemical techniques

Which of the following is correct for hydbridization of C-atom?

  1. $CH _{4}-SP^{3}$
  2. $C _{2}H _{4}-sp^{2}$
  3. $C _{2}H _{2}-sp$

  4. All of these
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

CH4− Alkane SP3

C2H4- Alkene SP2
C2H2- Alkyne SP

Hence all hybridization of carbon are correct

Multiple choice dielectric substances and polarization dielectrics and polarisation electrostatic potential and capacitance electrostatics physics

Which of the following is/are non-polar dielectrics?

  1. $HCL$

  2. Water

  3. Benzene
  4. $NH _3$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Ammonia and $HCl$ are polar molecules since they have a net dipole moment towards a particular direction. Both water and benzene are non-polar molecules. But water is a conductor of electricity, whereas benzene is a dielectric (insulator).

Multiple choice dielectric substances and polarization dielectrics and polarisation electrostatic potential and capacitance electrostatics physics

Which of the following is polar dielectrics?

  1. $HCL$
  2. $NH _3$
  3. $H _2O$

  4. All of the above
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Polar dielectric are those in which center of positive and negative charge is not same due to their shapes. 

$HCl$ , $NH _{3}$ and $H _{2}O$ all are polar dielectrics due to their high dielectric constant formed due to the difference in the polarity.

Multiple choice chemistry p- block elements-ii anomalous properties of nitrogen nitrogen - 15 group group 15 elements

Nitrogen forms stable $N _{2}$ molecule but phosphorus is converted to $P _{4}$ from $P _{2}$ because:

  1. p$\pi$-p$\pi$ bonding is strong in phosphorus
  2. p$\pi$-p$\pi$ bonding is weak in phosphorus

  3. triple bond is present in phosphorus
  4. single $P - P$ bond is weaker than $N -N$ bond
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

$P$ has empty $d$ orbital, that can be filled by an additional electron. And since its size is bigger it is least likely to handle triple bond, as size increases $\pi$ overlapping decreases. 

Multiple choice chemistry p- block elements-ii anomalous properties of nitrogen nitrogen - 15 group group 15 elements

Which of the following mlecular $P\pi -P\pi $ bond?

  1. ${ NO } _{ 3 }^{ - }$

  2. CO
  3. ${ CO } _{ 3 }^{ -2 }$
  4. ${ NO } _{ 4 }^{ -2 }$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

CO (carbon monoxide) has a π bond between carbon and oxygen where both atoms contribute p-orbitals - a pπ-pπ bond. Nitrate and carbonate ions have resonance, and nitrate ion does not contain a double bond structure.

Multiple choice chemistry p- block elements-ii anomalous properties of nitrogen nitrogen - 15 group group 15 elements

Which of the following  molecules is having $2p\pi -3d\pi $ bond?

  1. ${ SO } _{ 3 }$
  2. ${ NO } _{ 3 }^{ - }$
  3. ${ SO } _{ 2- }^{ 4 }$
  4. ${ PO } _{ 3- }^{ 4 }$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

In sulfur trioxide (SO3), sulfur utilizes its empty d-orbitals to form pi bonds with the p-orbitals of oxygen atoms, resulting in p_pi-d_pi bonding. The other species listed either lack vacant d-orbitals of appropriate energy or do not form d-pi bonds in the same manner.

Multiple choice chemistry p- block elements-ii anomalous properties of nitrogen nitrogen - 15 group group 15 elements

The type of bond between the atoms in a nitrogen molecule is :

  1. hydrogen bond

  2. ionic bond

  3. polar covalent bond

  4. pure covalent bond

  5. metallic bond
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The atomic number of nitrogen is 7.

Its electronic configuration is $[He]{ 2s }^{ 2 }{ 2p }^{ 5 }$
To complete its octet it needs 3 electrons.
As the bonding is between 2 nitrogen atoms each of the atom will share 3 electrons with other to complete their octet.
Sharing of electrons results in covalent bonding.
Hence, they form pure covalent bonds.

Multiple choice chemistry p- block elements-ii anomalous properties of nitrogen nitrogen - 15 group group 15 elements

Nitrogen form $N _2$, but phosphorous form $P _2$, it's at a time convert in $P _4$, reason is : -

  1. Triple bond present between phosphorous atom
  2. $p _\pi p _\pi$bonding is weak
  3. $p _\pi p _\pi$bonding is strong

  4. Multiple bond form easilly
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Phosphorus is unable to form $p\pi-p\pi$ bonds due to larger atomic size. So, $P$ atom is linked with $P$ atoms using $3$ sigma bonds. On the other hand, Nitrogen forms $1-\sigma$ and $2-\pi$ bonds i.e.,  triple bonds and exists as diatomic molecules.

Multiple choice chemistry p- block elements-ii anomalous properties of nitrogen nitrogen - 15 group group 15 elements

Which of the following has $p\pi -d\pi $ bonding?

  1. ${ NO } _{ 3 }^{ - }$
  2. ${ CO } _{ 3 }^{ - }$
  3. ${ BO } _{ 3 }^{ - }$
  4. ${ SO } _{ 3 }^{ - }$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

$p\pi-d\pi$ bonding includes d-orbitals,if you observe the options only S belongs to $3^{rd}$ period and has d-orbitals(though unoccupied in ground state).

Other options $C$ and $N$ belongs to $2^{nd}$ period while B belongs to $1^{st}$ period and doesn't have d-orbitals.

Multiple choice chemistry p- block elements-ii anomalous properties of nitrogen nitrogen - 15 group group 15 elements

Which of the following statements is correct ?

  1. In trisilylamine $p\pi - d\pi $ back bonding takes place.
  2. These are two $p\pi - d\pi $ bonds in molecule.

  3. Fraction of s-character in hybride around the central atom in molecule is 0.5
  4. ${\left( {{\text{C}}{{\text{H}} _{\text{3}}}} \right) _{\text{3}}}{\text{COH}}$ is more acidic than ${\left( {{\text{C}}{{\text{H}} _{\text{3}}}} \right) _{\text{3}}}{\text{SiOH}}$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

In trisilylamine N(SiH3)3, the nitrogen uses its lone pair to form pπ-dπ back bonds with empty d-orbitals of silicon. This is similar to back bonding in trimethylamine N-oxide. Option B is incorrect (no count given), Option C's hybrid claim is questionable, and Option D is wrong - silanols are more acidic than alcohols.