Which of the following statements best describes what it means for the acid-base reaction between acetic acid and water to be in equilibrium?
A) The mass of acetic acid and acetate is equal.
B) The number of moles of acetate equals the number of moles of acetic acid.
C) The number of moles of hydronium equals the number of moles of water.
D) The forward and reverse reactions proceed at the same rate.
E) The reaction is balanced.

Question

Which of the following statements best describes what it means for the acid-base reaction between acetic acid and water to be in equilibrium? 
A) The mass of acetic acid and acetate is equal. 
B) The number of moles of acetate equals the number of moles of acetic acid. 
C) The number of moles of hydronium equals the number of moles of water. 
D) The forward and reverse reactions proceed at the same rate. 
E) The reaction is balanced.

Quizplus · Accepted Answer

When an acid-base reaction is in equilibrium, it means that the forward and reverse reactions are occurring at the same rate. In this case, the reaction between acetic acid and water can form acetate and hydronium ions in the forward direction, while in the reverse direction, acetate and hydronium ions can react to form acetic acid and water. At equilibrium, the rate of the forward reaction is equal to the rate of the reverse reaction. Therefore, choice D is the correct answer. Choices A, B, C, and E do not accurately describe what it means for an acid-base reaction to be in equilibrium.

Which of the Following Statements Best Describes What It Means