Metre scales are made up of which alloy?

Fill in the blanks:
$1.$ Heating lanthanoids with sulfur gives .......
$2.$ Mixed oxides of lanthanoids are used as catalysts in ..........

The oxidation states of transition metal atoms in $K_{2}Cr_{2}O_{7}$,$KMnO_{4}$ and $K_{2}FeO_{4}$,respectively,are $x$,$y$ and $z$. The sum of $x$,$y$ and $z$ is

The total number of $Mn=O$ bonds in $Mn_2O_7$ is

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

List-$I$ (Transition metal/Compound/complex)	List-$II$ (Catalytic Role)
$A$. $V_2O_5$	$I$. Preparation of ammonia from $N_2/H_2$ mixture
$B$. $Fe$	$II$. Polymerisation of alkynes
$C$. $PdCl_2$	$III$. Preparation of $H_2SO_4$ from $SO_2$
$D$. $Ni$ complex	$IV$. Oxidation of ethyne to ethanal

$ \uparrow Y_{(g)} \xleftarrow{KI} CuSO_4 \xrightarrow{dil. H_2SO_4} X (\text{Blue colour}) $. $X$ and $Y$ are: