Question

In which of the following, ∆S is positive?

Options

• \[\ce{N2O4_{(g)} ⇌ 2NO2_{(g)}}\]

• \[\ce{2SO2_{(g)} + O2_{(g)} ⇌ 2SO3_{(g)}}\]

• \[\ce{H2_{(g)} + F2_{(g)} ⇌ 2HF_{(l)}}\]

• \[\ce{H2_{(g)} + 1/2O2_{(g)} ⇌ H2O_{(l)}}\]

Answer 1

\[\ce{N2O4_{(g)} ⇌ 2NO2_{(g)}}\]

Explanation:

1. ∆n_g = 2 − 1 = 1

2. ∆n_g = 2 − 3 = −1

3. ∆n_g = 0 − 2 = −2

4. ∆n_g = 0 − 1.5 = −1.5

For a given reaction, the number of gaseous product molecules increases, randomness increases.

∴ ∆S is positive reaction.