$A$ substance that increases the activity of a catalyst is known as ........

Which of the following statements is true for a catalyst?

Two percent of ethanol is added during the oxidation of chloroform to stop the formation of carbonyl chloride. In this reaction,ethanol acts as:

Formation of ammonia from $H_2$ and $N_2$ by Haber's process using $Fe$ is an example of

In a chemical reaction,a catalyst . . . . .

Which of the following catalyses the conversion of glucose into ethanol?