$\mathrm{EAN}$(Effective atomic number) of platinum in $\left[\mathrm{Pt}{\left({\mathrm{NH}}_3\right)}_6\right]{\mathrm{Cl}}_4$is $86$. The atomic number of $\mathrm{Pt}$ is ______.

${\mathrm{K}}_4\left[\mathrm{Fe}{\left(\mathrm{CN}\right)}_6\right]$ is

($\mathrm{i}$) potassium hexacyanoferrous ($\mathrm{II}$)

($\mathrm{ii}$) potassium hexacyanoferrate ($\mathrm{II}$)

($\mathrm{iii}$) potassium ferrocyanide

($\mathrm{iv}$) hexacyanoferrate ($\mathrm{III}$) potassium

CORRECT answer is _______.

Consider the following arrangements of the octahedral complex ion ${\left[\mathrm{Co}{\left({\mathrm{NH}}_3\right)}_4{\mathrm{Cl}}_2\right]}^{+}$.

Which of the following statements is INCORRECT?