In Haber's process, the final product ammonia is converted into:

Explanation

In the Haber's process, ammonia (NH3) is synthesized in the gaseous state from nitrogen (N2) and hydrogen (H2) under high pressure and temperature with an iron catalyst. The question focuses on what happens to ammonia after its formation. Ammonia gas is typically converted into a liquid state by cooling and pressurizing, which facilitates its separation from unreacted nitrogen and hydrogen gases and allows for easier transportation and storage. Therefore, Option B, 'Liquid state,' is correct. Option A is incorrect because ammonia is not converted into a solid state under these conditions. Option C is incorrect because, while ammonia is produced as a gas, the question asks about its conversion. Option D is incorrect because Option B provides the correct answer.