Q1: Reaction of orthophosphoric acid with phosphate rock produces

ANS:B - triple superphosphate

Triple superphosphate (TSP) is a type of phosphorus fertilizer that is produced through the reaction of phosphate rock with phosphoric acid. Here's an explanation of its composition, production, and use:

1. Composition: Triple superphosphate consists primarily of phosphorus (P), with little to no nitrogen (N) or potassium (K). The phosphorus content in TSP is usually around 46% to 48% P2O5 (phosphorus pentoxide), making it an excellent source of phosphorus for plants.
2. Production: Triple superphosphate is produced by reacting phosphate rock (which typically contains calcium phosphate minerals) with phosphoric acid (H3PO4). This reaction forms soluble calcium dihydrogen phosphate (Ca(H2PO4)2), also known as monocalcium phosphate, along with gypsum (calcium sulfate) as a byproduct. The soluble monocalcium phosphate is then further processed to form TSP crystals. The manufacturing process involves drying the wet TSP crystals to produce the final granular or powdered form of the fertilizer.
3. Nutrient Release: Unlike some other phosphorus fertilizers, such as diammonium phosphate (DAP) or monoammonium phosphate (MAP), TSP does not contain nitrogen. It provides only phosphorus, which is released gradually in the soil over time. The water-soluble phosphorus in TSP becomes available to plants through microbial processes and soil chemistry, promoting root development, flowering, fruiting, and overall plant growth.
4. Advantages: Triple superphosphate has several advantages as a phosphorus fertilizer. It is relatively cost-effective compared to other phosphorus fertilizers, making it suitable for large-scale agricultural applications. TSP is also less hygroscopic than some other phosphorus fertilizers, meaning it absorbs less moisture from the atmosphere and remains free-flowing and easy to handle.
5. Application: Triple superphosphate is typically applied to the soil as a basal fertilizer before planting or as a top-dressing fertilizer during the growing season. It can be broadcast, band-applied, or incorporated into the soil, depending on the specific crop and soil conditions. TSP is suitable for a wide range of crops, including cereals, oilseeds, vegetables, fruits, and legumes.

Overall, triple superphosphate is an important phosphorus fertilizer that provides essential nutrients to plants, promotes healthy growth, and improves crop yields. Its high phosphorus content and cost-effectiveness make it a valuable tool for sustainable agriculture and soil fertility management.