Consider the following statements: While diluting concentrated nitric acid solution 1. the concentration of [H₃O⁺] ions/volume increases 2. water must be added slowly to concentrated acid 3. acid must be added slowly to water Which of the statements given above is/are correct?

Diluting a concentrated acid like nitric acid involves specific chemical and safety principles. Statement 1 is incorrect because dilution results in a decrease in the concentration of hydronium ions ([H₃O⁺]) per unit volume, as the same number of ions is distributed over a larger volume of solvent [1]. Regarding safety, the process of mixing strong acids with water is highly exothermic. If water is added to concentrated acid (Statement 2), the intense heat generated can cause the mixture to splash out violently or break the glass container [1]. Therefore, the correct laboratory procedure is to always add acid slowly to water (Statement 3) while stirring. This ensures that the small amount of heat released is absorbed by the larger volume of water, preventing dangerous splattering. Thus, only statement 3 is correct.

Sources

1. [1] Science , class X (NCERT 2025 ed.) > Chapter 2: Acids, Bases and Salts > Activity 2.10 > p. 24