$H_2C=CH_2 + O_2 \xrightarrow{\text{aqueous medium}} CH_3CHO$. What is the catalyst used in the above green reaction?

Platinised asbestos helps in the formation of $SO_3$ from $SO_2$ and $O_2$. But,if even a small amount of $As_2O_3$ is present,the platinised asbestos does not help in the formation of $SO_3$. $As_2O_3$ acts here as

Match the catalysts to the correct processes:

Catalyst	Process
$A. TiCl_4$	$i. \text{Wacker process}$
$B. PdCl_2$	$ii. \text{Ziegler-Natta polymerization}$
$C. CuCl_2$	$iii. \text{Contact process}$
$D. V_2O_5$	$iv. \text{Deacon's process}$

Match the following.

List-$I$ (Reaction)	List-$II$ (Catalyst)
$A$. $N_{2(g)} + 3H_{2(g)} \longrightarrow 2NH_{3(g)}$	$I$. $Ni$
$B$. $2H_{2(g)} + O_{2(g)} \longrightarrow 2H_2O_{(l)}$	$II$. $Pt$
$C$. $CO_{(g)} + 3H_{2(g)} \longrightarrow CH_{4(g)} + H_2O_{(g)}$	$III$. $ZnO-Cr_2O_3$
$D$. $CO_{(g)} + 2H_{2(g)} \longrightarrow CH_3OH_{(g)}$	$IV$. $Fe$

The correct answer is:

The role of a catalyst is to change $ . . . . . . $.

Match the catalyst given in List-$I$ with the process in List-$II$.

List-$I$ (Catalyst)	List-$II$ (Process)
$A$. $Ni$ in presence of $H_2$	$1$. Ziegler-Natta catalyst
$B$. $Cu_2Cl_2$	$2$. Contact process
$C$. $V_2O_5$	$3$. Hydrogenation of vegetable oils
$D$. Finely divided iron	$4$. Sandmeyer reaction
$E$. $TiCl_4 + Al(CH_3)_3$	$5$. Haber process
	$6$. Decomposition of $KClO_3$