Final Answer:
The solution in an ammonia absorption system is A) ammonia.
Step-by-step explanation:
In an ammonia absorption system, the solution used is primarily composed of ammonia dissolved in water. This solution forms the working fluid in the absorption refrigeration cycle, where the ammonia acts as the refrigerant and water serves as the absorbent. The ammonia-water solution is pivotal in this system as it facilitates the absorption and release of heat, enabling the refrigeration process to occur efficiently.
The solution's composition plays a critical role in the cycle's operation. Typically, in such systems, the concentration of ammonia in the water varies based on the system's design and intended operating conditions. For instance, a common concentration could be around 20% ammonia by weight dissolved in water. This specific concentration provides optimal performance within the cycle, allowing for effective heat transfer and refrigeration capabilities.
The ammonia-water solution's properties, such as its boiling and absorption characteristics, ensure the successful operation of the absorption refrigeration system. The selection of ammonia as the refrigerant and water as the absorbent is due to their compatible properties, allowing for an efficient and environmentally friendly cooling process. Overall, the ammonia solution's composition and properties are fundamental to the functionality and effectiveness of the ammonia absorption system in providing cooling or refrigeration.