The correct option is C △Gvaporization<0 at 410 K and 1 atm
At Svap=△HBoiling Point=40×1000400=100 J/mol. K
(A) If the external pressure is 2 atm, then B.P>400 K
Since boiling point will increase △Svap<100
(B) At 400 K, and 1 atm, ΔSvaporization is 100 J/mol. K
(C) △G=△H−T△S
△G=40×1000−410×100=−1000 J
△G<0
(D) △H=△U+△ngRT
40=△U+1×8.314×10−3×400
△U=36.67 kJ/mol