ANS:A - dilute H₂SO₄

Phosphoric acid is produced in the wet process from phosphate rock and concentrated sulfuric acid (H2SO4). In the wet process, phosphate rock is reacted with concentrated sulfuric acid to produce phosphoric acid according to the following chemical equation: \text{Ca\text{(PO}_4\text{)}}_2 + 4\text{H}_2\text{SO}_4 \rightarrow 2\text{CaSO}_4 + 4\text{H}_3\text{PO}_4 This reaction forms phosphoric acid (H3PO4) and calcium sulfate (CaSO4), commonly known as gypsum. Phosphoric acid is then separated from the reaction mixture through processes such as filtration, evaporation, and crystallization. It is an essential chemical used in various industrial applications, including fertilizer production, food and beverage processing, and the manufacture of detergents and pharmaceuticals.