Filling a test tube almost completely with hydrochloric acid (HCl) before adding metal is unwise due to the vigorous reaction that can occur, potentially causing the acid to bubble over and create a safety hazard. The reaction between acid and metal can produce gas, leading to overflow that may harm the user. It is essential to prioritize safety in the lab, as improper handling of chemicals can lead to accidents. Additionally, there are warnings against consuming alcohol before conducting chemistry experiments, as it impairs judgment and increases risk. Proper lab practices are crucial for safe experimentation.
