a system consisting of 2 kg of water initially at 160°c, 10 bar undergoes an internally reversible, isothermal expansion during which there is energy transfer by heat into the system of 700 kj.

I believe the correct answers from the choices listed above are the first two options. The molecules O2- and F2+ are expected to have one unpaired electron. This can be determined by looking at the value of the charge. Hope this answers the question.