Chemistry: chapter 10- Chemical Bonding

Q/A

In which of the following compound does the central atom obey the octet rule?

d) SCl₂

In the molecule O_A = C = O_B, the formal charge on O_A, C and O_B are respectively.

d) 0, 0, 0

Which of the following is electron deficient?

c) BH₃

Which of the following molecule contain no π bond?

d) H₂O

The ratio of number of sigma (σ) bond and pi (π) bonds in 2 – butynal is

a) 8/3

Which one of the following is the likely bond angles of sulphur tetrafluo-ride molecule?

d) 89°, 117°

Assertion:
Oxygen molecule is paramagnetic.
Reason :
It has two unpaired electron in its bonding molecular orbital

c) assertion is true but reason is false.

According to Valence bond theory, a bond between two atoms is formed when

b) half filled atomic orbitals overlap

In ClF₃, NF₃ and BF₃ molecules the chlorine, nitrogen and boron atoms are

d) sp³d, sp³ and sp hybridised respectively

When one s and three p orbitals hybridise,

b) four equivalent orbitals at 109°28’ to each other will be formed

Which of these represents the correct order of their increasing bond order.

d) O₂^2- < C₂⁺ < O₂ < C₂^2-

Hybridisation of central atom in PCl₅ involves the mixing of orbitals.

c) s, p_x, p_y, p_z, d_{x² – y²}

The correct order of O – O bond length in hydrogen peroxide, ozone and oxygen is

b) O₂ > O₃ > H₂O₂

Which one of the following is diamagnetic?

b) O₂²

Bond order of a species is 2.5 and the number of electrons in its bonding molecular orbital is formed to be 8. The no. of electrons in its antibonding molecular orbital is

a) three

Shape and hybridisation of IF₅ are

c) Square pyramidal, sp³d²

Pick out the incorrect statement from the following:

c) All five sp³d hybrid orbitals are not equivalent out of these five sp³d hybrid orbitals, three are at an angle of 120° remaining two are perpendicular to the plane containing the other three

The molecules having same hybridisation, shape and number of lone pairs of electrons are

a) SeF₄, XeO₂F₂

In which of the following molecules / ions BF₃, NO₂^– H₂0 the central atom is sp² hybridised?

c) BF₃ and NO₂^–

Some of the following properties of two species, NO₃^– and H₃O⁺ are described below. Which one of them is correct?

a) dissimilar in hybridisation for the central atom with different structure

The types of hybridisation on the five-carbon atom from right to left in the, 2,3 pentadiene.

a) sp³, sp², sp, sp², sp³

XeF₂ is isostructural with

d) ICl₂^–

The percentage of s-character of the hybrid orbitals in methane, ethane, ethene, and ethyne are respectively

a) 25, 25, 33.3, 50

Of the following molecules, which have shape similar to carbondioxide?

c) C₂H₂

According to VSEPR theory, the repulsion between different parts of electrons obey the order

c) 1. p – 1. p > b. p – 1. p > b. p – b. p

Shape of ClF₃ is

c) “T” Shaped

Non – Zero dipole moment is shown by

d) water

Which of the following conditions is not correct for resonating structures?

c) the resonance hybrid should have higher energy than any of the contributing structure.

Among the following, the compound that contains, ionic, covalent, and Coordinate linkage is

a) NH₄Cl

CaO and NaCl have the same crystal structure and approximately the same radii. If U is the lattice energy of NaCl, the approximate lattice energy of CaO is

d) 4U

Define Bond order

The number of bonds formed between the two bonded atoms in a molecule is called the bond order.

Define Hybridisation

Hybridisation is the process of mixing of atomic orbitals of the same atom with comparable energy to form an equal number of new equivalent orbitals with the same energy.

Define σ – bond

When two atomic orbitals overlap linearly along the axis, the resultant bond is called a sigma (σ) bond.

What is a pi – bond?

When two atomic orbitals overlap sideways, the resultant covalent bond is called a pi (π) bond. When we consider x-axis as the molecular axis, the p_y – p_y and p_z – p_z overlaps will result in the formation of a π – bond.

What is dipole moment?

The polarity of a covalent bond can be measured in terms of dipole moment which is defined as
μ = q × 2d
Where μ is the dipole moment, q is the charge and 2d is the distance between the two charges. The dipole moment is a vector and the direction of the dipole moment vector points from the negative charge to positive charge.

The unit of dipole moment is coloumb meter (C m). It is usually expressed in Debye unit (d). The conversion factor is 1 Debye = 3.336 × 10^-30 C m.

Linear form of carbondioxide molecule has two polar bonds. Yet the molecule has Zero dipole moment. Why?

The linear form of carbon dioxide has zero dipole moment, even though it has two polar bonds. In CO₂, the dipole moments of two polar bonds (CO) are equal in magnitude but have opposite direction. Hence, the net dipole moment of the CO₂ is,

Which bond is stronger σ or π? Why?

1. Sigma bonds (σ) are stronger than Pi bonds (π). Because, sigma bonds are formed from bonding orbitals directly between the nuclei of the bonding atoms, resulting in greater overlap and a strong sigma bond (axial overlapping).

2. π bonds result from the overlap of atomic orbitals that are in contact through two areas of overlap (lateral overlapping). Pi bonds are more diffused bonds than sigma bonds.

Define Bond Energy

The bond enthalpy is defined as the minimum amount of energy required to break one mole of a particular bond in molecules in their gaseous state. The unit of bond enthalpy is kJ mol^-1.

considering x-axis as the molecular axis which out of the following will form a sigma bond.
i) 1s and 2p_y
ii) 2p_x and 2p_y
iii) 2p_x and 2p_z
iv) 1s and 2p_z

i) 1s and 2p_y: No sigma bond
ii) 2p_x and 2p_y: sigma bond
iii) 2p_x and 2p_z: No sigma bond
iv) 1s and 2p_z: No sigma bond

What type of hybridization is possible in the following geometries?

1. octahedral

2. tetrahedral

3. square planar

1. octahedral: sp³d²

2. tetrahedral: sp³

3. square planar: dsp²