ANS:A - Urea

Urea is a nitrogen-containing organic compound with the chemical formula CO(NH2)2. It is one of the most widely used nitrogen fertilizers in agriculture and has various other industrial applications. Here are some key points about urea:

1. Composition: Urea is composed of carbon, nitrogen, hydrogen, and oxygen atoms. It is a white, crystalline solid at room temperature, but it can also be produced in granular or prilled forms for use as a fertilizer.
2. Nitrogen Content: Urea has a high nitrogen content, typically around 46% by weight. This makes it an efficient source of nitrogen for plants, as nitrogen is an essential nutrient required for various biological processes, including photosynthesis, protein synthesis, and overall plant growth.
3. Production: Urea is produced industrially through the reaction of ammonia (NH3) with carbon dioxide (CO2) under high pressure and temperature in the presence of a catalyst. This process, known as the Haber-Bosch process, allows for the synthesis of urea on a large scale. Additionally, urea can be produced biologically in organisms as a metabolic waste product.
4. Fertilizer Use: Urea is commonly used as a nitrogen fertilizer in agriculture to provide essential nitrogen nutrients to plants. It is particularly suitable for crops with high nitrogen requirements, such as cereals, oilseeds, and leafy vegetables. Urea can be applied to the soil as a basal fertilizer before planting or as a top-dressing fertilizer during the growing season. It can also be applied through irrigation systems as a foliar spray.
5. Nitrogen Release: Upon application to the soil, urea undergoes hydrolysis, a process where it reacts with water to form ammonium ions (NH4+) and bicarbonate ions (HCO3-). The ammonium ions are then converted into nitrate ions (NO3-) through microbial processes in the soil, making nitrogen available for plant uptake. This gradual release of nitrogen from urea helps to minimize nitrogen losses through leaching and volatilization.
6. Other Applications: In addition to its use as a fertilizer, urea has various other industrial applications. It is used as a raw material in the production of plastics, adhesives, and resins. It is also used in the manufacture of urea-formaldehyde resins, which are commonly used as adhesives in plywood and particleboard production.