Which type of isomerism is exhibited by the isomers $[Co(NH_3)_5(SO_4)]Br$ and $[Co(NH_3)_5Br]SO_4$?

Calculate the magnetic moment of a divalent ion in aqueous solution if its atomic number is $25$. (in $BM$)

Match List-$I$ with List-$II$.

List-$I$ (Complex)	List-$II$ (Type of isomerism)
$A$. $[Co(NH_3)_5(NO_2)]Cl_2$	$I$. Solvate isomerism
$B$. $[Co(NH_3)_5(SO_4)]Br$	$II$. Linkage isomerism
$C$. $[Co(NH_3)_6][Cr(CN)_6]$	$III$. Ionization isomerism
$D$. $[Co(H_2O)_6]Cl_3$	$IV$. Coordination isomerism

Choose the correct answer from the options given below:

Select the correct code of $TRUE$ and $FALSE$ for the given statements:
$(a)$ Peroxide ion as well as dioxygen molecule both are paramagnetic species.
$(b)$ In the set of isomers,$[Cr(H_2O)_6]Cl_3$ and $[CrCl(H_2O)_5]Cl_2 \cdot H_2O$,both compounds can easily lose water molecules on treatment with conc. $H_2SO_4$.
$(c)$ During the transformation $NO \to NO^+$,bond length decreases and magnetic behavior changes from paramagnetic to diamagnetic.
$(d)$ An ether is more volatile than an alcohol,both having the same molecular formula.

What is the magnetic moment of a divalent ion in aqueous solution if its atomic number is $28$ (in $BM$)?

$A$ reaction of cobalt $(III)$ chloride and ethylenediamine in a $1:2$ mole ratio generates two isomeric products $A$ (violet coloured) and $B$ (green coloured). $A$ can show optical activity,but $B$ is optically inactive. What type of isomers do $A$ and $B$ represent?