While diluting an acid, why is it recommended that the acid should be added to water and not water to the acid?

When diluting an acid, it is recommended to add the acid to water and not water to the acid. This is a safety precaution due to the exothermic nature of the dilution process.

Adding water to acid is potentially more dangerous because the reaction between water and concentrated acid is highly exothermic, meaning it releases a significant amount of heat. If water is added too quickly to concentrated acid, the heat generated can cause the water to boil, and there’s a risk of splattering concentrated acid. This can lead to dangerous situations, including the potential for acid burns or other injuries.

On the other hand, adding acid to water allows for better control of the process. The acid is added gradually to the water while stirring, and the heat is more effectively dissipated. This method reduces the risk of rapid heating and boiling, minimizing the chances of splattering or other safety hazards.

The recommended order of mixing, “add acid to water,” is often remembered by the acronym “AAW” (Always Add Water). Following this guideline helps ensure a safer dilution process when working with concentrated acids.