Which of the following elements can be involved in $\mathrm{p\pi } - \mathrm{d\pi }$ bonding?

• Carbon

• Nitrogen

• Phosphorus

• Boron

Which one ofthe following statements about C₂ molecule is wrong?

• The bond order of C₂ is 2.

• In vapour phase, C₂ molecule is diamagnetic.

• Double bond in C₂ molecule consists of both $\mathrm{\pi }$- bonds because of the presence of 4${\mathrm{e}}_{\mathrm{s}}^{-}$ in two $\mathrm{\pi }$- molecular orbitals.

• double bond in C₂ molecule consists of one $\sigma$- bond and on $\mathrm{\pi }$-bond.

The type of hybridisation in SF₆, molecule is

• sp³d

• dsp³

• sp³d

• d²sp³

Among LiCl, BeCl₂, BCl₃ and CCl₄ the covalent bond character follows the order

• LiCl < BeCl₂ < BCl₃ < CCl₄

• BCl₃ < CCl₄ < BeCl₂ < LiCl

• BeCl₂ < LiCl < CCl₄ < BCl₃

• CCl₄ < BCl₃ < BeCl₂ < LiCl

Which of the following has sp²-hybridisation?

• C₂H₆

• C₂H₄

• BeCl₂

• C₂H₂

An sp³-hybrid orbital contains

• $\frac{1}{4} \mathrm{s}- \mathrm{character}$

• $\frac{1}{2} \mathrm{s}- \mathrm{character}$

• $\frac{2}{3} \mathrm{s}-\mathrm{character}$

• $\frac{3}{4} \mathrm{s}-\mathrm{character}$

Hybridisation states of C in CH${}_3^{+}$ and C${\mathrm{H}}_3^{-}$ are

• sp², sp³

• sp³, sp²

• sp, sp²

• sp², sp

Which one of the following complexes is outer orbital complex?

• [Co(NH₃)₆]³⁺

• [Mn(CN)₆]⁴⁺

• [Fe(CN)₆]^4-

• [Ni(NH₃)₆]²⁺

The correct statement with regard to ${\mathrm{H}}_2^{+}$ and ${\mathrm{H}}_2^{-}$ is

• both H${}_2^{+}$ and H${}_2^{-}$ are equally stable

• both H${}_2^{+}$ and H${}_2^{-}$ do not exist

• H${}_2^{-}$ is more stable than H${}_2^{+}$

• H${}_2^{+}$ is more stable than H${}_2^{-}$

450.

The number of electrons, neutrons and protons in a species are equal to 10, 8 and 8 respectively. The proper symbol of the species is

• ${}_8{}^{16}\mathrm{O}$

• ${}_8{}^{18}\mathrm{O}$

• ${}_{10}{}^{18}\mathrm{Ne}$

• ${}_8{}^{16}\mathrm{O}^{2-}$