(2005? Baotou) As shown in the figure, the conical flask contains substance Y (which can be gas, solution or solid), the liquid X is contained in the separating funnel, and the liquid X is contained in the U-shaped tube. (1) If the liquid level A in the U-shaped tube is higher than the liquid level B, it means that the pressure of the gas in the conical flask is lower than the external atmospheric pressure, so if X is water, the conical flask should be filled with water-soluble gases, such as ammonia, carbon dioxide and hydrogen chloride. Or ammonium nitrate, which will lower the temperature in the flask when dissolved in water.

(2) If the liquid level A in the U-shaped tube is lower than the liquid level B, it means that the pressure of the gas in the conical bottle is higher than the outside atmospheric pressure, so the possible combination is substances that can react with water to release heat, such as quicklime and water, or substances that release heat when dissolved in water, such as sodium hydroxide and concentrated sulfuric acid.

So the answer is: (1)NH4NO3 or CO2, NH3, HCl gas, etc.

(2)① concentrated H2SO4 and water; ? ② water and CaO；; ③ Water and solid sodium hydroxide ..

All the other answers are correct.