While analyzing driving forces for a chemical reaction it is observed that energy and entropy are true forces. The entropy is a typical state function owing to the possibility of calculation of its absolute value. The absolute values of entropies can be compared an calculating by knowing the residual entropies at `0 K` and by calculating the change due to change of state. Using the given information and data for a particular substance x answer the questions that follow :
Useful data :
(p) Standard melting point and boiling point of `x` is `200 K` and `400 K` respectively.
(q) `DeltaH_("fusion")^(@) = 10 kcal//"mole"` and `DeltaH_(vap)^(@) = 80 kcal//"mole"`.
(r) `C_(p.m)(s) x = 0.1T cal//K "mole" , C_(p.m) (l) x = 0.05 Tcal//K "mole`
`S_(m.40 K)^(@)s_(x) = 5 cal//"mole"`
Which of the following statement is/are true ?

Options

A. Substance x will be a perfect crystals.
B. `S_(m,N_(2)O_(4))^(@)` = two times `S_(m.N_(2)O_(4))^(@)`
C. `DeltaS_("fusion")` of x will be temperature dependent
D. `DeltaH_("fusion",300K)^(@) lt 10` kcal//"mole"`

Answer

c,d