Concept:The asbestos, usually platinized asbestos, is placed in the reaction vessel to act as a catalyst for the oxidation of sulphur dioxide.
Explanation:In the contact process, sulphur dioxide gas is oxidised by oxygen gas.
The reaction is:
2SO2(g)+O2(g)⇌2SO3(g)This reaction is very slow without a catalyst.
Platinized asbestos speeds up the reaction by providing an active catalyst surface for the reacting gases.
It is not used to absorb impurities, dry the gas, or solidify it.
Thus, the purpose of the asbestos in the diagram is to catalyze the formation of sulphur trioxide.
Answer:B. catalyze the reaction
