There are three bottles of chemical fertilizers in the laboratory without labels, only knowing that they are ammonium bicarbonate (NH 4 HCO 3), ammonium chloride (NH 4 Cl) and urea [CO(NH 2) 2].

(1) urea ammonium bicarbonate ammonium chloride

(2)No. (3)No. (4) NH 3 H2O

This topic examines students' ability to analyze and solve problems by distinguishing ammonium salt from carbonate. Ammonium salt can react with alkaline substances to produce ammonia with pungent smell, but urea can't; Carbonate can react with acid to produce gaseous carbon dioxide, so A is urea, B is ammonium bicarbonate and C is ammonium chloride. (2) In Experiment II, if the medicine is not taken alone, it contains calcium chloride and calcium carbonate generated with hydrated lime. After adding hydrochloric acid, there are still two different phenomena that will not affect the experimental results. (3) At room temperature, ammonium bicarbonate can decompose, but ammonium chloride can't, so it can be identified by smelling it.