The p-Block Elements

The magnetic nature of boron molecule is same as the magnetic nature of

• nitrogen molecule

• carbon molecule

• unipositive nitrogen molecule

• oxide ion

Which of the following is not a true alum?

• Na₂SO₄.Al₂(SO₄)₃.24H₂O

• MgSO₄.Cr₂(SO₄)₃.24H₂O

• K₂SO₄.Cr₂(SO₄)₃.24H₂O

• (NH₄)₂SO₄.Fe(SO₄)₃.24H₂O

The densities of graphite and diamond at 298 K are 2.25 and 3.31 g cm^-3 respectively. If the standard free energy difference is 1895 J mol^-1, the pressure at which graphite will be transformed into diamond is

• 9.92 × 10⁸ Pa

• 9.92 × 10⁷ Pa

• 9.92 × 10⁶ Pa

• None of these

Which one of the following elements does not form triiodide on reacting with iodine?

• B

• Ti

• Al

• Ga

An example of covalent solid is

• MgO

• Mg

• SiC

• CaF₂

The order of covalent character of KF, KI, KCl is

• KCl < KF < KI

• KI < KCl < KF

• KF < KI < KCl

• KF < KCl < Kl

Which one of the following forms a basic oxide?

• B

• Tl

• Al

• Ga

The gas produced by the passage of air over hot coke is

• carbon monoxide

• carbon dioxide

• producer gas

• water gas

Inorganic graphite is

• B₂H₆

• BN

• BF₃

• B₂N₃H₆

The bonding in diborane (B₂H₆) can be described by

• 4 two centre - two electron bonds and 2 three - centre- two electron bonds

• 3 two centre - two electron bonds and 3 three - centre- two electron bonds

• 2 two centre - two electron bonds and 4 three centre - two electron bonds

• 4 two centre - two electron bonds and 4 two- centre- two electron bonds