The pair having the similar shape is

• BF₃ and NF₃

• ${\mathrm{BF}}_4^{-} \mathrm{and} {\mathrm{NH}}_4^{+}$

• ${\mathrm{SiCl}}_4 \mathrm{and} {\mathrm{SCl}}_4$

• ${\mathrm{CH}}_3^{+} \mathrm{and} {\mathrm{H}}_3{\mathrm{O}}^{+}$

Which one of the following molecules has zero dipole moment?

• NO${}_2^{+}$

• H₂O

• NH₃

• CO

243.

Pick out the isoelectronic structures from the following

 $$\begin{gathered} {\mathrm{CH}}_3^{+}; {\mathrm{H}}_3{\mathrm{O}}^{+}; {\mathrm{NH}}_3; {\mathrm{CH}}_3^{-} \\ \mathrm{I} \mathrm{II} \mathrm{III} \mathrm{IV} \end{gathered}$$

• I and II

• I and III

• I and IV

• II, III and IV

Which of the following will have the shape of a trigonal bipyramid?

• PF₃Cl₂

• IF₅

• BrF₅

• SbF${}_5^{2-}$

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