a. the aqueous hydrogen ion (H+) is the only species for which ΔH°f, S°, and ΔG°f each have a value of zero at
25°C
b. S° ≠ 0 for each of the elements in its standard state at 25°C</p>
<p>c. ΔH°f, S°, and ΔG°f each have a value of zero for each of the elements in its standard state at 25°C
d. ΔG°f = 0 for each of the elements in its standard state at 25°C
e. ΔH°f = 0 for each of the elements in its standard state at 25°C</p>