Answer: H⁺.
- A OH⁻
- B H⁺
- C Na⁺
- D Cl⁻
Correct answer: B. H⁺
Explanation: An Arrhenius acid furnishes H⁺ (as H₃O⁺) in water; a base furnishes OH⁻.
As the reaction proceeds, reactant concentration falls and product concentration rises until both level off at equilibrium.
Concept context
When forward and reverse reaction rates are equal, equilibrium is reached. Learn about Kc, Kp, Le Chatelier's principle, and acid-base equilibria, including pH, buffer solutions, and solubility product.