Option 1: The statement that aluminum hydroxide is amphoteric in nature is correct. Amphoteric substances can behave as both acids and bases, and aluminum hydroxide can react with both acids and bases. It can act as a base by accepting protons from acids and as an acid by donating protons to bases.
Option 2 (Correct): The statement that aluminum occurs in the free state in nature is not correct. Aluminum is a highly reactive metal and does not occur in its elemental form in nature. Instead, it is found in various minerals, primarily bauxite, which is an ore consisting of aluminum oxide.
Option 3: The statement that nitric acid hardly affects aluminum at all is incorrect. Nitric acid can react with aluminum, causing it to dissolve and form aluminum nitrate.
Option 4: The statement that hot concentrated sulfuric acid gives sulfur dioxide with aluminum is correct. When aluminum reacts with hot concentrated sulfuric acid, it produces sulfur dioxide gas and aluminum sulfate. This reaction is commonly used in the laboratory to produce sulfur dioxide.