Strong acid

Definition

A strong acid is a substance that completely dissociates in water, releasing a high concentration of hydrogen ions (H+) into the solution. This complete ionization leads to a very low pH value, typically below 3, and signifies its ability to donate protons readily in acid-base reactions, making it a crucial concept in understanding Brønsted-Lowry and Lewis acid-base theories.

5 Must Know Facts For Your Next Test

1. Strong acids include substances like hydrochloric acid (HCl), sulfuric acid (H2SO4), and nitric acid (HNO3), all of which dissociate completely in water.
2. The degree of ionization for strong acids is virtually 100%, meaning they do not establish an equilibrium between the undissociated acid and its ions.
3. In the context of the Brønsted-Lowry theory, strong acids are proton donors that significantly increase the concentration of H+ ions in a solution.
4. Strong acids can react with strong bases to form water and a salt in a neutralization reaction, releasing a significant amount of energy.
5. When mixing strong acids with water, the reaction is highly exothermic, and safety precautions should be taken to prevent splashes and burns.

Review Questions

• Compare and contrast strong acids with weak acids in terms of their dissociation in water.
  • Strong acids completely dissociate in water, leading to a high concentration of hydrogen ions (H+), while weak acids only partially dissociate. This means that in solutions of strong acids, nearly all the acid molecules break apart into ions, resulting in low pH values. In contrast, weak acids establish an equilibrium between undissociated molecules and their ions, resulting in higher pH values compared to strong acids.
• Discuss how strong acids fit into the Brønsted-Lowry theory of acids and bases, including their role as proton donors.
  • According to the Brønsted-Lowry theory, strong acids act as proton donors because they readily release H+ ions into solution. When a strong acid donates a proton to a base, it forms a conjugate base that is typically very weak. This rapid donation of protons contributes to the characteristic low pH values of strong acid solutions and highlights their effectiveness as acid-base reactants in chemical reactions.
• Evaluate the implications of using strong acids in industrial applications and laboratory settings, particularly regarding safety and chemical reactivity.
  • Using strong acids in industrial applications and labs has significant implications for both safety and chemical reactivity. Their complete ionization means that they can aggressively react with various substances, including metals and organic compounds, which can lead to hazardous situations such as corrosive damage or exothermic reactions. As such, proper safety measures—including protective gear and proper storage—are essential when handling these substances to prevent accidents and ensure safe operations.

Related terms

dissociation: The process by which an acid separates into its ions in solution, allowing for the release of H+ ions in the case of strong acids.

pH scale: A numerical scale ranging from 0 to 14 that measures the acidity or basicity of a solution, with values below 7 indicating acidity, where strong acids typically fall.

conjugate base: The species that remains after an acid donates a proton; for strong acids, the conjugate base is usually very weak and has little tendency to re-associate with H+.