The number of $\sigma$ bonds,$\pi$ bonds and lone pair of electrons in pyridine,respectively are:

The ratio of lone pair of electrons to bond pair of electrons in an ozone $(O_3)$ molecule is

The ionic bond is absent in

Which of the following statement$(s)$ is/are correct? [$T$ for True and $F$ for False$]$
$(a)$ Hybrid orbitals form stronger bonds than pure atomic orbitals.
$(b)$ Canonical structures have a difference in the arrangement of atoms $w.r.t.$ each other.
$(c)$ Any symmetrical molecule always contains the same bond angle.
$(d)$ $VSEPR$ theory can explain the square planar geometry of $XeF_4$.

The correct increasing order of the total number of $\sigma$ and $\pi$ bonds in the following structures is:
$I. \ H_2S_2O_6, \ II. \ H_2SO_3, \ III. \ H_2SO_5$

Which of the following pairs does not contain isoelectronic species?