Final answer:
In the production of Nitric Acid, concentrated Sulphuric Acid serves as a dehydrating agent by removing water and as a less volatile acid to drive the formation of Nitric Acid. The correct answer is option D.
Step-by-step explanation:
In the laboratory preparation of Nitric Acid, the role of concentrated Sulphuric Acid is to act as a dehydrating agent. Concentrated sulfuric acid has a strong affinity for water, which allows it to remove water from other compounds. This property is crucial in the preparation of Nitric Acid because it dehydrates the nitric oxide (NO) or nitrogen dioxide (NO2), which are formed during the oxidation of nitrate salts, to produce Nitric Acid (HNO3).
The reaction of concentrated sulfuric acid with nitrate salts also demonstrates another role: as a less volatile acid, it helps to drive the equilibrium towards the production of the more volatile Nitric Acid, which can then be condensed and collected.
While concentrated sulfuric acid can act as an oxidizing agent as well, in the context of Nitric Acid preparation, its primary function is not as an oxidizing or reducing agent.