Question

select the correct answer.
what can be inferred from the graph?
a + b \
ightleftharpoons c + d
graph: y-axis (concentration) from 0 to 45, x-axis (time (seconds)) from 0 to 16. red curve starts at (0, 40) decreasing; blue curve starts at (0, 0) increasing, both leveling off ~14 seconds.
\bigcirc a. the reaction reaches equilibrium at 2.75 seconds.
\bigcirc b. the amount of reactant is greater than the amount of product at equilibrium.
\bigcirc c. the reaction converts all the products back into reactants.
\bigcirc d. the amount of reactants and products is equal at 14 seconds.
\bigcirc e. the reaction between a and b is product favored.

Explanation:

• Option A: Equilibrium is when concentrations stop changing. At 2.75s, concentrations are still changing (lines not flat), so A is wrong.
• Option B: At equilibrium (after ~12s), product (blue) concentration (~40) is greater than reactant (red) concentration (~5), so B is wrong.
• Option C: The reaction is reversible ($\ce{A + B <=> C + D}$), but it doesn't convert all products back to reactants (equilibrium has both, and product concentration is higher), so C is wrong.
• Option D: At 14s (equilibrium), product concentration (~40) ≠ reactant concentration (~5), so D is wrong.
• Option E: At equilibrium, product concentration (C + D) is much higher than reactant concentration (A + B), so the reaction favors products (product - favored), so E is correct.

Answer:

E. The reaction between A and B is product favored.