The increasing order of bond order of O₂, O${}_2^{+}, {\mathrm{O}}_2^{-} \mathrm{and} {\mathrm{O}}_2^{2-}$ is

• ${\mathrm{O}}_2^{+} < {\mathrm{O}}_2 < {\mathrm{O}}_2^{-} < {\mathrm{O}}_2^{2-}$

• ${\mathrm{O}}_2^{2-} < {\mathrm{O}}_2^{-} < {\mathrm{O}}_2^{+} < {\mathrm{O}}_2$

• ${\mathrm{O}}_2 < {\mathrm{O}}_2^{+} < {\mathrm{O}}_2^{-} < {\mathrm{O}}_2^{2-}$

• ${\mathrm{O}}_2^{2-} < {\mathrm{O}}_2^{-} < {\mathrm{O}}_2 < {\mathrm{O}}_2^{+}$

Main axis of diatomic molecule is z. The orbitals p_x and p_y overlap to form

• $\mathrm{\pi }$-molecular orbital

• σ-molecular orbital

• δ-molecular orbital

• No bond is formed

Using MOT, compare ${\mathrm{O}}_2^{+} \mathrm{and} {\mathrm{O}}_2^{-}$ species and choose the inncorrect option.

• ${\mathrm{O}}_2^{+}$ have higher bond order than ${\mathrm{O}}_2^{-}$

• ${\mathrm{O}}_2^{-}$ is less stable

• ${\mathrm{O}}_2^{+}$ is diamagnetic while ${\mathrm{O}}_2^{-}$ is paramagnetic

• Both ${\mathrm{O}}_2^{-} \mathrm{and} {\mathrm{O}}_2^{+}$ are paramagnetic

Which of the following structure of a molecule is expected to have three bond pairs and one lone pair of electrons?

• Octahedral

• Trigonal planar

• Pyramidal

• Tetrahedral

275.

The paramagnetic molecule at ground state among the following is :

• H₂

• O₂

• N₂

• CO

The following salt shows maximum covalent character:

• AlCl₃

• MgCl₂

• CsCl

• LaCl₃

Which of the following is paramagnetic ?

• B₂

• C₂

• N₂

• F₂

The trigonal bipyramidal geometry results from the hybridisation :

• dsp³ or sp³d

• dsp² or sp²d

• d²sp³ or sp³d²

• d³p² or d²p³

The molecule having smallest bond angle is :

• H₂O

• H₂S

• NH₃

• H₂Te

Which of the following molecules has three-fold axis of symmetry ?

• NH₃

• C₂H₄

• CO₂

• SO₂