A. H2(g) + I2(g) ↔ 2HI(g)
B. 2NO2(g) ↔ N2O4(g)
C. PCl5(g) ↔ PCl3(g) + Cl2(g)
D. 2O3(g) ↔ 3O2(g)

Correct Answer:

Option A – H2(g) + I2(g) ↔ 2HI(g)

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