During the unfolding reaction of a helix, breakage of each hydrogen bond requires about 2kJ/mol. This implies hydrogen bonds are

ANS:D - slightly stronger in proteins than in water

What can be said about the thermodynamics of the unfolding of proteins as associated with H-bond breakage? Is it favorable?

I suppose entropy is increasing since the H-bonds are breaking, but at the same time the enthalpy term is +, so then the entropic effect here overweight the enthalpies effect and the reaction is favorable. It doesn't stop there because the energy being used to break the bonds is coming from an external source, so that is known as a coupling reaction thus why the breaking of the bonds can take place!

This has been an attempt for me to display what I have learned of the thermodynamics of biochemistry, and is not a credited answer, but a well articulated one using the laws of thermodynamics.