Question

State whether ∆S is positive, negative or zero for the reaction 2H_(g) → H_2(g). Explain.

Answer 1

(i) The given reaction, 2H_(g) → H_2(g) is the formation of H_2(g) from free atoms.

(ii) Since two H atoms form one H₂ molecule, ∆n = 1 – 2 = -1 and disorder is decreased.

Hence entropy change ∆S < 0 (or negative).