ANS:B - liquid NH₃

Liquid NH3 refers to liquid ammonia, which is anhydrous (meaning without water) and exists in liquid form at low temperatures and moderate pressures. Ammonia (NH3) is a compound composed of one nitrogen atom bonded to three hydrogen atoms. Here are some key points about liquid NH3:

1. Physical Properties: At standard atmospheric pressure, liquid ammonia has a boiling point of -33.34°C (-28.012°F) and a melting point of -77.73°C (-107.914°F). It is colorless and has a characteristic pungent odor. Liquid ammonia is less dense than water, and it can float on the surface of water.
2. Production: Liquid ammonia is typically produced through the Haber-Bosch process, which involves the reaction of nitrogen (N2) and hydrogen (H2) gases at high pressure and temperature in the presence of an iron-based catalyst. The resulting ammonia gas is then compressed and cooled to condense it into liquid form.
3. Uses: Liquid ammonia has numerous industrial applications, including:
   • Fertilizer Production: Liquid ammonia is a key raw material in the production of nitrogen-based fertilizers such as ammonium nitrate and urea.
   • Refrigeration: Liquid ammonia is commonly used as a refrigerant in industrial refrigeration systems due to its favorable thermodynamic properties.
   • Cleaning and Decontamination: Liquid ammonia is used as a cleaning agent in various industrial processes and as a decontaminant for surfaces and equipment.
   • Chemical Synthesis: Liquid ammonia is used as a solvent and reactant in various chemical synthesis processes, including the production of organic compounds and pharmaceuticals.
4. Safety Considerations: While liquid ammonia is a valuable industrial chemical, it can be hazardous if not handled properly. It is highly toxic and can cause severe irritation or burns upon contact with skin, eyes, or mucous membranes. Additionally, liquid ammonia poses a fire and explosion hazard when exposed to heat or flames.