Statement I: Very little hydrogen is produced when sulphuric acid is added to calcium. Statement II: The salt that is produced, calcium sulphate, is insoluble.

Statement I is true because the reaction between calcium and sulphuric acid produces very little hydrogen gas compared to other acids. Statement II is also true and provides the correct explanation. When calcium reacts with sulphuric acid, it forms calcium sulphate. Unlike many other metal salts, calcium sulphate is insoluble or only sparingly soluble in water. As the reaction begins, this insoluble salt forms a solid coating or layer on the surface of the calcium metal. This physical barrier prevents further contact between the acid and the metal, effectively stopping the reaction almost immediately. Consequently, the evolution of hydrogen gas ceases shortly after it starts, resulting in very little total hydrogen production. This behavior contrasts with reactions involving hydrochloric acid, where the resulting calcium chloride is highly soluble, allowing the reaction to proceed to completion.