A salt has the following standard thermodynamic data for dissolution at 298 K:
ΔH° = +15 kJ mol⁻¹ and ΔS° = +120 J mol⁻¹ K⁻¹.
Which of the following is the closest value of ΔG° (in kJ mol⁻¹) for the process, and what does it imply about spontaneity under standard conditions?
a) +21; the process is non-spontaneous
b) −21; the process is spontaneous
c) −36; the process is spontaneous
d) +15; the process is non-spontaneous