The number of ions present in $2.0 \ L$ of a solution of $0.8 \ M \ K_4[Fe(CN)_6]$ is

The configurations for the complex $[Co(en)(NH_3)_2Br_2]^+$ are shown. Which of the following statements is incorrect?

Which of the given statements is incorrect?

Select the correct code about complex $[Cr(NO_2)(NH_3)_5][ZnCl_4]$:
$(I)$ $IUPAC$ name of compound is pentaamminenitrito$-N$-chromium$(III)$ tetrachlorozincate$(II)$
$(II)$ It shows geometrical isomerism
$(III)$ It shows linkage isomerism
$(IV)$ It shows coordination isomerism

The correct option$(s)$ regarding the complex $[Co(en)(NH_3)_3(H_2O)]^{3+}$ $(en = H_2NCH_2CH_2NH_2)$ is (are):
$A$. It has two geometrical isomers
$B$. It will have three geometrical isomers if bidentate 'en' is replaced by two cyanide ligands
$C$. It is paramagnetic
$D$. It absorbs light at longer wavelength as compared to $[Co(en)(NH_3)_4]^{3+}$

$0.001 \ mol$ of $Co(NH_3)_5(NO_3)(SO_4)$ was passed through a cation exchanger. The acid coming out of it required $20 \ mL$ of $0.1 \ M$ $NaOH$ for neutralization. Hence,the complex is: