Final answer:
Na₂CO₃ (sodium carbonate) and NH₄OH (ammonium hydroxide) are soluble in water due to general solubility rules, while PbBr₂ (lead(II) bromide) is insoluble, and CaSO₄ (calcium sulfate) is usually considered insoluble due to its limited solubility.
Step-by-step explanation:
To determine the solubility of the compounds in water: Na₂CO₃ (sodium carbonate), PbBr₂ (lead(II) bromide), NH₄OH (ammonium hydroxide), and CaSO₄ (calcium sulfate), we can refer to general solubility rules. According to these rules:
All compounds of group 1 cations (which includes Na⁺) and NH₄⁺ are soluble, making Na₂CO₃ and NH₄OH soluble in water.
Most bromides are soluble, but those combined with Pb²⁺ are an exception, thereby making PbBr₂ insoluble in water.
Many sulfates are soluble, but CaSO₄ is slightly soluble with some conditions leading to it being classified as insoluble in certain contexts.
Therefore, we can conclude that Na₂CO₃ and NH₄OH are soluble in water, while PbBr₂ is insoluble, and CaSO₄ has limited solubility, often considered insoluble in general classroom settings.