In aqueous solution, boric acid ${\mathrm{H}}_3{\mathrm{BO}}_3$ is a:

Which one of the following statements is not true? 

Select the correct set of statements for an acid type indicator used in a titration:
$\left(\mathrm{i}\right)$ In general, $\mathrm{pH}$ range of an indicator is $\left({\mathrm{pK}}_{\mathrm{a}}-1\right)$ to $\left({\mathrm{pK}}_{\mathrm{a}}+1\right)$ and indicator shows its characteristic colours in this range.

$\left(\mathrm{ii}\right)$ In general, $\mathrm{pH}$ range of an indicator is $\left({\mathrm{pK}}_{\mathrm{a}}-1\right)$ to $\left({\mathrm{pK}}_{\mathrm{a}}+1\right)$ and indicator does not show its characteristic colours in this range.

$\left(\mathrm{iii}\right)$ In the relation : $\mathrm{pH}={\mathrm{pK}}_{\mathrm{In}}+{\log }_{10}\frac{\left[{\ln }^{-}\right]}{\left[\mathrm{Hln}\right]}, \mathrm{pH}$ value represents $\mathrm{pH}$ of indicator solution.

$\left(\mathrm{iv}\right)$ In the relation : $\mathrm{pH}={\mathrm{pK}}_{\mathrm{In}}+{\log }_{10}\frac{\left[{\ln }^{-}\right]}{\left[\mathrm{Hln}\right]}, \mathrm{pH}$ value represents $\mathrm{pH}$ of resulting solution containing indicator.