O Levels Chemistry (5070)•5070/12/M/J/18
Explanation
Equilibrium in Chemical Reactions
Steps:
- Identify the reaction as reversible, indicated by the double arrow ⇌.
- Recall that equilibrium occurs when rates of forward and reverse reactions balance.
- Evaluate each option against the definition of dynamic equilibrium.
- Select the option matching the equal rates condition.
Why B is correct:
- By definition, chemical equilibrium means forward and reverse reaction rates are equal, so concentrations remain constant.
Why the others are wrong:
- A: At equilibrium, concentrations do not change with time.
- C: ΔH = +170 kJ/mol shows the forward reaction is endothermic and absorbs heat.
- D: Both sides have 2 molecules (1 N₂ + 1 O₂ = 2; 2 NO = 2).
Final answer: B
Topic: Reversible reactions and equilibrium
Practice more O Levels Chemistry (5070) questions on mMCQ.me