The strength of the covalent bond in ${\mathrm{H}}_2$, ${\mathrm{F}}_2$ and $\mathrm{HF}$ is in the order

How many bonds are there in:

For $\mathrm{A}-\mathrm{B}$ bond if percent ionic character is plotted against electronegativity difference $\left({\mathrm{\chi }}_{\mathrm{A}}-{\mathrm{\chi }}_{\mathrm{B}}\right)$, the shape of the curve would look like

Arrange the following compounds in order of increasing dipole moment

Toluene (I), m-dichlorobenzene (II), o-dichlorobenzene (Ill), p-dichlorobenzene (IV)