Which of the following metal ions has a purple color?

The magnetic moment of $2.84 \, B.M.$ is exhibited by which of the following ions? (Atomic numbers: $Ni = 28, Ti = 22, Cr = 24, Co = 27$)

Calculate the number of unpaired electrons in the following gaseous ions: $Mn^{3+}, Cr^{3+}, V^{3+}$ and $Ti^{3+}$. Which one of these is the most stable in aqueous solution?

Which one of the following is correct for all elements from $Sc$ to $Cu$?

Match List-$I$ with List-$II$:

List-$I$ ($\text{Transition metal ion}$)	List-$II$ ($\text{Spin only magnetic moment (B.M.)}$)
$A$. $Ti^{3+}$	$I$. $3.87$
$B$. $V^{2+}$	$II$. $0.00$
$C$. $Ni^{2+}$	$III$. $1.73$
$D$. $Sc^{3+}$	$IV$. $2.84$

Choose the correct answer from the options given below:

$A$ transition metal $M$ among $Sc, Ti, V, Cr, Mn$ and $Fe$ has the highest second ionisation enthalpy. The spin only magnetic moment value of $M^{+}$ ion is $. . . . . . . BM$ (Near integer)
(Given atomic number $Sc: 21, Ti: 22, V: 23, Cr: 24, Mn: 25, Fe: 26$)