To determine which of the processes listed are exothermic, we first need to understand what an exothermic reaction is. An exothermic process is one that releases energy, usually in the form of heat, to its surroundings. Let's analyze each option provided to see which ones fit this definition.
Analyzing Each Process
1. Reaction of Water with Quicklime
This process involves the reaction of calcium oxide (quicklime) with water to form calcium hydroxide. This reaction is highly exothermic, releasing a significant amount of heat. Therefore, this process is exothermic.
2. Dilution of an Acid
When an acid is diluted with water, it typically absorbs heat from the surroundings, making this process endothermic. The heat is absorbed to break the bonds in the acid and to mix it with water. Thus, this is not an exothermic process.
3. Evaporation of Water
Evaporation is the process where liquid water turns into vapor. This requires energy to overcome the intermolecular forces holding the water molecules together. As a result, evaporation is an endothermic process, as it absorbs heat from the environment.
4. Sublimation of Camphor Crystals
Sublimation is the transition of a substance from a solid to a gas without passing through the liquid phase. This process also requires energy to break the bonds in the solid state, making it endothermic. Therefore, sublimation is not exothermic.
Conclusion on Exothermic Processes
Based on the analysis:
- Process (i) - Reaction of water with quicklime: Exothermic
- Process (ii) - Dilution of an acid: Not exothermic
- Process (iii) - Evaporation of water: Not exothermic
- Process (iv) - Sublimation of camphor: Not exothermic
From the options given, the only exothermic process is (i). Therefore, the correct answer is A. (i) and (ii) is not correct since (ii) is endothermic. The other options also do not include (i) as an exothermic process. So, the final answer is that only the reaction of water with quicklime is exothermic.
