Chemistry · EQUILIBRIUM

Consider the following statements concerning the dynamic nature of chemical equilibrium: (A) At dynamic equilibrium, the forward and reverse reactions cease completely. (B) The dynamic nature of the synthesis of ammonia was confirmed using deuterium, where mixed forms like \( \text{NH}_2\text{D} \), \( \text{NHD}_2 \), and \( \text{HD} \) were detected in mass spectrometry. (C) Chemical equilibrium can only be attained when starting from pure reactants, not from pure products. (D) At equilibrium, the concentrations of reactants and products remain constant because their rates of formation and consumption are equal. How many of the above statements are correct?

1. A
   Only one
2. B
   Only two
3. C
   Only three
4. D
   All four