Which one of the following,when dissolved in water,gives a coloured solution in a nitrogen atmosphere?

Match the following:

List-$I$ (Aquated Ion)	List-$II$ (Colour)
$A. Ni^{2+}$	$I. \text{Violet}$
$B. Fe^{3+}$	$II. \text{Blue}$
$C. Mn^{3+}$	$III. \text{Yellow}$
$D. V^{4+}$	$IV. \text{Red}$
	$V. \text{Green}$

On heating $Mn(OH)_2$ with $PbO_2$ and conc. $HNO_3$,a pink colour is obtained due to the formation of:

The number of terminal oxygen atoms present in the product $B$ obtained from the following reaction is $....$
$4FeCr_2O_4 + 8Na_2CO_3 + 7O_2 \rightarrow 8Na_2CrO_4 + 2Fe_2O_3 + 8CO_2$
$2Na_2CrO_4 + 2H^{+} \rightarrow B + H_2O + 2Na^{+}$

Which of the following are used as catalysts in petroleum cracking?

The alloy that contains copper and $Zn$ is $x$ and the one that contains copper and $Ni$ is $y$. What are $x$ and $y$ respectively?