Question

Submit Which of the following best describes the reaction? 2 H2S(g) + 3 O2(g) → 2 H2O(g) + 2 SO2(g) A) AS has a large negative value. B) ASº has a small negative value. C) AS has a large positive value. D) AS has a small positive value. E) AS is zero.
0 and AS

Answer 1

Answer:  B) $\Delta S^0$ has a small negative value.

Explanation:

Entropy is the measure of randomness or disorder of a system. If a system moves from  an ordered arrangement to a disordered arrangement, the entropy is said to decrease and vice versa.

$\Delta S$ is positive when randomness increases and $\Delta S$ is negative when randomness decreases.

$2H_2S(g)+3O_2(g)\rightarrow 2H_2O(g)+2SO_2(g)$

As there are 5 moles of gaseous reactants and 4 moles of gaseous products, the gaseous molecules are decreasing on moving from reactants to products, thus randomness decreases and $\Delta S$ is negative.      

Thus  $\Delta S^0$ has a small negative value.