Question

For the reaction, $$ H_2(g) + I_2(g) \rightleftharpoons 2HI(g) $$ Attainment of equilibrium is predicted correctly by: 

• A.
• B.
• C.
• D.

Hint:

At equilibrium, the concentrations of reactants and products become constant, and the reaction rate of the forward and reverse reactions become equal.

Answer 1

The Correct Option is C

- For the reaction at equilibrium, the concentrations of the reactants (\( H_2 \) and \( I_2 \)) decrease, and the concentration of the product (\( HI \)) increases over time.
- As the system reaches equilibrium, the concentration of the reactants will stabilize and the product concentration will also stabilize. Thus, the graph where the concentrations of \( H_2 \) and \( I_2 \) decrease and the concentration of \( HI \) increases correctly represents the attainment of equilibrium.

Final Answer: Option (3).

Answer 2

Step 1: Understand the reaction.
The given reaction is: \[ H_2(g) + I_2(g) \rightleftharpoons 2HI(g). \] This is a reversible reaction where hydrogen (H₂) and iodine (I₂) react to form hydrogen iodide (HI).

Step 2: Analyze the graph.
The graph shows the molar concentration of H₂, I₂, and HI as a function of time. The concentrations of H₂ and I₂ decrease as the reaction proceeds, while the concentration of HI increases. Eventually, the concentrations of all the species level off, indicating that equilibrium has been reached. At equilibrium, the rates of the forward and reverse reactions are equal, and the concentrations remain constant.

Step 3: Conclusion.
The graph correctly shows the attainment of equilibrium. The concentrations of the reactants (H₂ and I₂) decrease, and the concentration of the product (HI) increases until a constant value is reached for all three species, indicating equilibrium.

Final Answer:
\[ \boxed{\text{The graph in the image correctly predicts the attainment of equilibrium.}} \]