511.

The example of σ-complex is

• Fe(η⁵-C₅H₅)₂

• [Cr(CO)₆]

• Al₂(CH₃)₆

• Zeiss salt

The bond present in N₂O₅ are

• only ionic

• covalent and coordinate

• only covalent

• covalent and ionic

Which of the following statements is false?
1. Non-bonding pairs occupy more space than bonding pairs.

2. The bonding orbitals in trigonal bipyramidal molecule are described as sp³d hybrids.

3. SnCl₂ has linear shape.

4. PCl${}_4^{+}$ and AlCl${}_4^{-}$ are isoelectronic.

• 1

• 2

• 3

• 4

The correct order of increasing C-O bond length of CO, CO₂ and CO${}_3^{2-}$ is

• CO${}_3^{2-}$ < CO₂ < CO

• CO₂ < CO${}_3^{2-}$ < CO

• CO < CO${}_3^{2-}$ < CO₂

• CO < CO₂ < CO${}_3^{2-}$

Covalent compounds have low melting point because

• covalent molecules are held by weak van der Waal's force of attraction

• covalent bond is less exothermic

• covalent bond is weaker than ionic bond

• covalent molecules have definite shape

The bond order in CN^- ion is

• 2.5

• 3

• 2

• 3.5

Chemical bond implies

• attraction and repulsion

• attraetion and repulsion balanced at a particular distance

• attraction

• repulsion

The percentage s-character of the hybrid orbitals in methane, ethene and ethyne are respectively

• 25, 33, 50

• 25, 50, 75

• 50, 75, 100

• 10, 20, 40

Which of the following represents the Lewis structure of N₂ molecule?

For a stable molecule, the value of bond order must be

• there is no relationship between stability and bond order

• zero

• positive

• negative