Which of the following statement is correct?

Acid should be added to water slowly.

The correct answer is option 2. Acid should be added to water slowly.

The process of dissolving an acid or a base in water is highly exothermic. The acid must always be added slowly to water with constant stirring. If water is added to a concentrated acid, the heat generated may cause the mixture to splash out and cause burns. The glass container may also break due to excessive local heating.