A). B2F4 (g) has the largest entropy.
The state of matter with the highest entropy is gas. The state of matter that has the lowest entropy is solid. From highest to lowest it goes: goes gas > liquid > solid.
So choice E can be eliminated as (s) means it’s solid and will have the lowest entropy. Choice D can also be eliminated as (l) means it is liquid. Now the choices left are all gases.
B2F4 is Diboron tetrafluoride, and has a standard entropy of about 318 J mol/K. It’s molecular weight is 97.6156 g/mol.
BF3 is Boron trifluoride, and has a standard entropy of about 254 J mol/K. It’s molar mass is 67.81 g/mol.
B2H6 is Diborane, and has a standard entropy of about 232 J mol/K. It’s molar mass is 27.66 g/mol.
B2F4 is a covalent compound. B2F4 (g) has the highest molecular weight, so it will have a larger molar entropy. Atoms with larger mass usually contain more particles, so a gas with the most moles will have the higher entropy.