Change in enthalpy and entropy when sugar dissolves in water We know that dissolution of sugar in water is a spontaneous process.
So, change in Gibbs free energy $(ΔG)$ must be negative for the overall process:
$$ΔG = ΔH - TΔS &lt; 0$$
Hence either the enthalpy or entropy must drive the reaction.
Now, after searching for the values, most websites suggest the process is endothermic (i.e. $ΔH &gt; 0).$
But Jan's answer has me convinced that the overall entropy of a system should decrease (i.e. increase in entropy of sugar molecules is outweighed by decrease in entropy of water molecules).
So, what's the real reason for reaction to be spontaneous if neither entropy and enthalpy are driving the reaction?
The entropy change for ideal mixing is $\Delta S=-R(x_A\ln{x_A}+x_B\ln{x_B})$