The efficiency of a catalyst depends on which of the following?

When acidified $KMnO_4$ is added to hot oxalic acid solution,the decolourization is slow in the beginning,but becomes very rapid after some time. This is because :

The decomposition of $H_2O_2$ can be slowed by the addition of a small amount of acetamide. The latter acts as a

Match the following:

List-$I$ (Reaction)	List-$II$ (Catalyst)
$A$. Hydrogenation of vegetable oils	$I$. $Ni$
$B$. Decomposition of potassium chlorate	$II$. $MnO_2$
$C$. Oxidation of $SO_2$ in lead chamber process	$III$. $Pt$
$D$. Oxidation of ammonia in Ostwald's process	$IV$. $NO_{(g)}$

The correct answer is

In which of the following processes does shape-selective catalysis occur?

The catalyst used in the manufacture of methanol from water gas is