Chemical Bonding

Question 1

A chemical bond is formed due to following two reasons

Answer 1

To lower down the potential energy, and to increase stability

To attain noble gas configuration by completing its octet.

Question 2

Ionic bond is also known as

Answer 2

electrovalent Bond and non-directional bond.

Question 3

Atom which is having less, electronegativity should have

Answer 3

low ionization energy

Question 4

The atom, which is having high electronegativity should have

Answer 4

high electron affinity.

Question 5

The alkali metals and alkaline earth metals, one combined with nonmetals form,

Answer 5

ionic bonds.

Question 6

LiCl is having more …….. nature.

Answer 6

covalent

Hence, it is more soluble in pyridine and acetone

Question 7

BeCl2 is also having

Answer 7

covalent bond.

Question 8

AlCl3 is covalent and forms,

Answer 8

dimer are to Al2Cl6,

But in aqueous solution due to high hydration enthalpy of Al3+ and Cl- it becomes ionic in nature.

Question 9

Define lattice energy.

Answer 9

It is the energy required to break one mole of ionic solid into its gaseous ions.

Question 10

Define enthalpy of formation.

Answer 10

It is the energy required or released when one mole of the compound is formed from standard state of its element.

Question 11

Standard state of different elements

Answer 11

Hydrogen is gas
Fluorine is gas
Chlorine is gas
Oxygen is gas
Sodium is solid.
Magnesium is solid
Potassium is solid
Iodine is solid
Carbon is solid
Bromine is liquid
Mercury is liquid

Question 12

Calculation of lattice enthalpy is done by

Answer 12

Born Haber Cycle

Question 13

Lattice enthalpy is proportional to

Answer 13

Q+Q- / r+r-

Q + is the charge of cation.
Q- is the charge of anion.
r+ is the radius of cation.
r- is the radius of anion.

Question 14

Hydration enthalpy.

Answer 14

It is the energy released. When one mole of the compound is dissolved in excess of water.

In case of any other solvent, it is known as solvation enthalpy.
It will be always exothermic.

Question 15

Hydration energy is proportional to

Answer 15

Q+*Q-

1/r+ * 1/r-

Question 16

The compound will be soluble only if

Answer 16

|HE| > |LE|

Question 17

Solubility is proportional to

Answer 17

the size difference between anion and cation.

Lesser the difference lesser will it be soluble.
Greater the difference more will it be soluble

F- and OH- are small anions.

Question 18

Find the solubility order of NaCl and NaF in nonpolar solvent,

Answer 18

NaCl > NaF

Question 19

In case of alkali metals the charge density of … is maximum

Answer 19

Li+ is maximum,
hence it attracts more number of water molecules and forms tertiary hydrated layre.
Hence ionic mobility of Li+ aq is least.

Question 20

Hydrated ion size

Answer 20

Li+ > Na+ > K+ > Rb+ > Cs+

F- > Cl- > Br- > I-

Question 21

Ionic Stability G1

Answer 21

Li+ < Na+ < K+ < Rb+ < Cs+

Question 22

Ionic size G1

Answer 22

Li+ < Na+ < K+ < Rb+ < Cs+

Question 23

Ionic mobility comparison in Li+aq and Be2+aq

Answer 23

Li+aq > Be2+aq

Question 24

Methods to draw dot and cross structure.

Answer 24

Generally central atom would be the least electronegative atom.

H and F will never be the central atoms.

The number of 0H bonds will be the basicity of the acid.

When the octet of an atom is completed and the lone pair is left, it can participate in coordinate bond formation.

Between any two atoms, only one coordinate bond is possible.

Question 25

Limitations of octet rule.

Answer 25

It was not able to explain the formation of electron deficient and species.

It was not able to explain the odd is electron molecules.

It was not able to explain the formation of super octet and expanded octet or hypervalent molecules

In case of third period elements and above in element that is in elements which can expand their octet, double bonds is preferred over coordinate bond.

Question 26

Criteria to draw the bond structure

Answer 26

The bond structure of a molecule should explain the properties of the molecule and bond structure we are able to draw by knowing the properties.

Question 27

Why does PH5 not exist?

Answer 27

In case of Ph5, due to less electronegativity of H atom, it is not able to excite the s orbital electrons of phosphorus into the d orbital and hence PH5 does not exist.

Same is the case with SH4 and SH6.

Question 28

What is homolytic Fission?

Answer 28

When in a single bond one electron is accepted by each atom in fission, it is known as homolytic fission.

In this case, free radicals are formed.

Question 29

Why do inert gases don’t form compounds

Answer 29

In case of inert gases, they do not form bond because of their octet is complete.

But in case of xenon due to its less ionization energy, it is able to form covalent bond with more electronegative elements like fluorine and oxygen.