Final answer:
Following the 'AAA - Always Add Acid' rule helps to avoid the dangerous exothermic reactions that can occur when diluting strong acids. However, certain procedures, like making piranha solution, may require adding substances to acid following strict safety protocols. Understanding the specifics of each situation, including acid-base reactions with salts, is crucial for safety and accuracy in chemical handling.
Step-by-step explanation:
When considering whether to add acid to a solution or the other way around, the key thing to remember is the exothermic nature of acidic dissolution and the potential danger of splattering. The mnemonic 'AAA - Always Add Acid' is an important safety guideline for diluting concentrated acids, as adding water to acid can cause a violent reaction where the solution can heat and splatter, potentially causing burns. This is especially true for strong acids like sulfuric acid.
However, there are certain situations, such as preparing piranha solution (a mixture of sulfuric acid and hydrogen peroxide), where the protocol might require adding a specific reagent to the acid instead. In these cases, the procedures are designed with the specific reactivity and safety considerations of the chemicals in mind, and deviating from these procedures can be dangerous.
Similarly, in cases involving acid-base reactions with salts, the final pH of the solution will not always be neutral. Hydrolysis can lead to solutions being slightly acidic or basic depending on the relative strengths of the acid and base involved. Understanding these chemical properties and following Standard Operating Procedures (SOPs) closely can help ensure safety and accuracy in chemical preparation.