Find the formal charge on each oxygen atom and the P–O bond order in the phosphate ion (PO₄³⁻), respectively.

1. -0.75, 0.6

2. -0.75, 1.0

3. -0.75, 1.25

4. -3.1, 1.25

Which of the following pairs of compounds is isoelectronic and isostructural?
(1) BeCl_2, XeF₂
(2) Tel_2, XeF₂
(3) ${\mathrm{IBr}}_2^{-}$_, XeF₂
(4) IF₃, XeF₂

The hybridisations of atomic orbitals of nitrogen in ${\mathrm{NO}}_2^{+},<mspace\; width="1em"></mspace>{\mathrm{NO}}_3^{-}$ and ${\mathrm{NH}}_4^{+}$ are

(a) sp, sp³ and sp²               (b) sp², sp³ and sp

(c) sp, sp² and sp³               (d) sp², sp and sp³

What is the dominant intermolecular force on bond that must be overcome in converting

liquid CH₃OH to a gas?

1. Hydrogen bonding

2. Dipole-dipole interaction

3. Covalent bonds

4. London dispersion force

Arrange the following compounds in the correct decreasing order of hydrogen-bond strength: