Which of the following species behave as strong acids or strong bases in aqueous solution? (a) H- (b) O2- (c) H2SO4 (d) CsOH

Verified step by step guidance

Step 1: Understand the definitions of strong acids and strong bases. Strong acids completely dissociate in water to produce H+ ions, while strong bases completely dissociate to produce OH- ions.

Step 2: Analyze each species. (a) H- is the hydride ion, which is not a strong acid or base. It can act as a base by accepting a proton to form H2.

Step 3: Analyze (b) O2-. The oxide ion is a strong base because it reacts with water to form OH- ions: O2- + H2O -> 2OH-.

Step 4: Analyze (c) H2SO4. Sulfuric acid is a strong acid because it completely dissociates in water to form H+ and HSO4- ions: H2SO4 -> H+ + HSO4-.

Step 5: Analyze (d) CsOH. Cesium hydroxide is a strong base because it completely dissociates in water to form Cs+ and OH- ions: CsOH -> Cs+ + OH-.

Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Strong Acids and Bases

Strong acids are substances that completely dissociate in water, releasing all their hydrogen ions (H+), while strong bases completely dissociate to release hydroxide ions (OH-). This complete ionization results in a high concentration of H+ or OH- in solution, leading to a significant change in pH. Common examples include hydrochloric acid (HCl) for strong acids and sodium hydroxide (NaOH) for strong bases.

Acid-Base Theory

Acid-base theory, particularly the Brønsted-Lowry theory, defines acids as proton donors and bases as proton acceptors. This framework helps in identifying the behavior of various species in aqueous solutions. For instance, H2SO4 is a strong acid because it donates protons readily, while CsOH is a strong base as it accepts protons effectively in solution.

Aqueous Solution Behavior

In aqueous solutions, the behavior of acids and bases is influenced by their ability to interact with water molecules. Strong acids and bases will significantly alter the concentration of H+ and OH- ions in the solution, respectively. Understanding this behavior is crucial for predicting the pH and reactivity of the solution, which is essential for answering questions about acid-base strength.

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