Question

what is the proper method of mixing acid and water​

Answer 1

When you mix acid with water, it's extremely important to add the acid to the water rather than the other way around. This is because acid and water react in a vigorous exothermic reaction, releasing heat, sometimes boiling the liquid. If you add acid to water, the water is unlikely to splash up, however, even if it did, it's less likely to cause injuries than if you make the mistake of adding water to acid. When you add water to acid, the water boils and the acid may splatter and splash!

Answer 2

D. When you mix acid with water, it's extremely important to add the acid to the water rather than the other way around. This is because acid and water react in a vigorous exothermic reaction, releasing heat, sometimes boiling the liquid.

This is mostly the case for sulfuric acid. Commercially available sulfuric acid is dense (~1.8 g/ml) and when water is added, it may not mix. In this case a layer of hot weak acid solution is formed, which boils and sprays around. When acid is poured into water, it flows down the flask and mixes much better, so no boiling occurs.

The reason this occurs is due to the large amount of energy released in the hydration reaction of sulfuric acid ions. Do not believe that heat comes from dissociation, as the dissociation of acids, bases, and salts always consumes energy. The energy is released from subsequent hydration, and the release may be high, especially if H+ or OH− ions are hydrated.

$\huge \underline \red{ \tt {hope \: this \: helps}}$