In the periodic table,metals usually used as catalysts belong to:

Match the properties given in List-$I$ with the metals given in List-$II$:

List-$I$ (Property)	List-$II$ (Metal)
$A$. Element with maximum second ionization enthalpy	$i$. $Co$
$B$. Element with maximum third ionization enthalpy	$ii$. $Cr$
$C$. $M$ in $M(CO)_6$	$iii$. $Cu$
$D$. Element with maximum enthalpy of atomization	$iv$. $Zn$
	$v$. $Ni$

For $Cr, Mn, Fe,$ and $Co$,the $E_{{M^{3+}}/{M^{2+}}}^{\circ}$ values are $0.41, +1.57, +0.77,$ and $+1.97 \ V$ respectively. Which of these metals is most easily oxidized from the $+2$ to the $+3$ oxidation state?

Which element from the following is the last element of the $5d$-transition series?

Which of the following ions exhibit the same value of spin-only magnetic moment? $(A)$ $Ti^{3+}$, $(B)$ $Cr^{3+}$, $(C)$ $Mn^{2+}$, $(D)$ $Fe^{3+}$, $(E)$ $Sc^{3+}$. Choose the most appropriate answer from the options given below.

Which of the following salts is colourless?