Among the following, the compound that contains ionic, covalent and co-ordinate linkage is

• NH₃

• NH₄Cl

• NaCl

• CaO

272.

A covalent molecule AB₃ has pyramidal structure. The number of lone pair and bond pair of electrons in the molecule are respectively

• 2 and 2

• 0 and 4

• 3 and 1

• 1 and 3

The magnetic moment of a transition metal ion is $\sqrt{15}$ BM. Therefore, the number of unpaired electrons present in it is

• 3

• 4

• 1

• 2

Which one of the following conversions involve change in both hybridisation and shape?

• CH₄ → C₂H₆

• NH₃ → NH${}_4^{+}$

• BF₃ → BF${}_4^{-}$

• H₂O → H₃O⁺

Peroxide ion ......
(i) has five completely filled antibonding molecular orbitals
(ii) is diamagnetic
(iii) has bond order one
(iv) is isoelectronic with neon
Which one of these is correct?

• (ii) and (iii)

• (i), (ii) and (iv)

• (i), (ii) and (iii)

• (i) and (iv)

When O₂ is converted into O${}_2^{+}$

• both paramagnetic character and bond order increase

• bond order decreases

• paramagnetic character increases

• paramagnetic character decreases and the bond order increases

Increasing order of carbon-carbon bond length for the following is

$\underset{\left(\mathrm{A}\right)}{{\mathrm{C}}_2{\mathrm{H}}_4} \underset{\left(\mathrm{B}\right)}{{\mathrm{C}}_2{\mathrm{H}}_2} \underset{\left(\mathrm{C}\right)}{{\mathrm{C}}_6{\mathrm{H}}_6} \underset{\left(\mathrm{D}\right)}{{\mathrm{C}}_2{\mathrm{H}}_6}$

• C < B < A < D

• B < C < A < D

• D < C < A < B

• B < A < C < D

Hybridised states of carbon in graphite and diamond are respectively

• sp³, sp³

• sp³, sp²

• sp², sp²

• sp² , sp³

Which of the following is not a characteristic of a covalent compound?

• No definite geometry

• Insoluble in polar solvent

• Smal difference in electronegativity between the combining atoms

• Low melting point

A ligand is a

• Bronsted acid

• either a Lewis acid or a Lewis base

• Lewis base

• Lewis acid