Chapter 16, Problem 67E

What happens to △G (becomes more negative or more positive) for the following chemical reactions when the partial pressure of oxygen is increased?

(a) $\text{S}\left(s\right)+{\text{O}}_2\left(g\right)\to {\text{SO}}_2\left(g\right)$

(b) $2{\text{SO}}_2\left(g\right)+{\text{O}}_2\left(g\right)\to 2{\text{SO}}_3\left(g\right)$

(c) $\text{HgO}\left(s\right)\to \text{Hg}\left(l\right)+{\text{O}}_2\left(g\right)$