An ideal gas is expand from `(p_(1),V_(1),T_(1))` to `(p_(2),V_(2),T_(2))` under different conditions. The correct statement(s) among the following is (are):

Options

A. The work done by the gas is less when it is expanded reversibly from `V_(1)` to `V_(2)` under adiabatic conditions as compared to that when expanded reversibly from `V_(1)` to `V_(2)` under isothermal conditions.
B. The change in internak energy of the gas is (i) zero, if it is expanded reversibly with `T_(1)=T_(2)` and (ii) Positive, if it is expanded reversibly under adibatic conditions with `T_(1) ne T_(2)`.
C. If the expansion is carried out freely, it is simultaneously both isothermal as well as adiabatic.
D. The work done on the gas is maximum when it is compressed irreversibly from `(p_(2)V_(2))` to `(p_(1)V_(1))` against constant pressure `p_(1)`.

Answer

A, C, D