Chemical Bonding

In N0^–₃ ion, the number of bond pairs and lone pairs of electrons on nitrogen atom are,

• 2, 2

• 3, 1

• 1,3

• 4, 0

Which of the following angle corresponds to sp² hybridisation?

• 90°

• 120°

• 180°

• 109°

Polarity in a molecule and hence the dipole moment depends primarily on electronegativity of the constituent atoms and shape of a molecule. Which of the following has the highest dipole moment?

• CO₂

• HI

• H₂O

• (a) SO₂

Which of the following is the correct order of dipole moment ?

• NH3 < BF3 < NF3 < H2O

• BF3 < NF3 < NH3 < H2O

• BF3 < NH3 < NF3 < H2O

• H2O < NF3 < NH3 < BF3

The species, having bond angles of 120° is

• ClF₃

• NCl₃

• BCl₃

• PH₃

The electronegativity difference between N and F is greater than that between N and H yet the dipole moment of NH₃ (1.5 D) is larger than that of NF₃ (0.2 D). This is because

• In NH₃ the atomic dipole and bond dipole are in the opposite directions whereas in NF₃ these are in the same direction

• In NH₃ as well as in NF₃ the atomic dipole and bond dipole are in the same direction

• In NH₃ the atomic dipole and bond dipole are in the same direction whereas in NF₃ these are in opposite directions

• In NH₃ as well as in NF₃ the atomic dipole and bond dipole are in opposite directions.

H₂O is dipolar, whereas BeF₂ is not. It is because

• The electronegativity of F is greater than that of O

• H₂O involves hydrogen bonding whereas BeF₂ is a discrete molecule

• H₂O is linear and BeF₂ is angular

• H₂O is angular and BeF₂ is linear

Predict the correct order among the following :

• Bond pair - bond pair > lone pair - bond pair > lone pair - lone pair

• Lone pair - bond pair > bond pair - bond pair > lone pair - lone pair

• Lone pair - lone pair > lone pair - bond pair > bond pair - bond pair

• Lone pair - lone pair > bond pair - bond pair > lone pair - bond pair

Which of the following species contains three bond pairs and one lone pair around the central atom?

• H₂O

• BF₃

• NH₃

• CO₂

Which of the following is not a correct statement?

• Multiple bonds are always shorter than corresponding single bonds

• The electron-deficient molecules can act as Lewis acids.

• The canonical structures have no real existence.

• Every AB₅ molecule does in fact have square pyramid structure