The number of nodal planes present in σ^* antibonding orbitals is

• 1

• 2

• 0

• 3

The overlapping of orbitals in benzene is of the type

• sp-sp

• p-p

• sp²-sp²

• sp³-sp³

The calculated bond order of superoxide ion ${\mathrm{O}}_2^{-} \mathrm{is}$

• 2.5

• 2

• 1.5

• 1

Mesomeric effect involves delocalisation of

• pi electrons

• sigma electron

• protons

• None of these

One mole of which of the following has the highest entropy?

• Liquid nitrogen

• Hydrogen gas

• Mercury

• Diamond

A ligand can also be regarded as

• Lewis acid

• Bronsted base

• Lewis base

• Bronsted acid

A gas deviates from ideal behaviour at a high pressure because its molecules

• attract one another

• show the Tyndall effect

• have kinetic energy

• are bound by covalent bonds

If one mole of ammonia and one mole of hydrogen chloride are mixed in a closed container to form ammonium chloride gas, then

• ΔH > ΔU

• ΔH = ΔU

• ΔH < ΔU

• there is no relationship

Three moles of PCl₃ three moles of PCl₃, and two moles of Cl, are taken in a closed vessel. If at equilibrium the vessel has 1.5 moles of PCl₅ the number of moles of PCl₃, present in it is

• 5

• 3

• 6

• 4.5

An octahedral complex is formed when hybrid orbitals of the following type are involved

• sp³

• dsp²

• d²sp³

• sp²d²