As `O_2` (I) is cooled at 1 atm pressure , it freezes to form solid I at 54.5 K. At a lower temperature , solid rearrange to solid II, which has a different crystal that for the phase transition solid to slid II , `DeltaH=-743.1 Jmol^(-1) and DeltaS=-17.0JK^(-1) mol^(-1)` . At what temperature are solids I and II in equilibrium ?

Options

A. 2.06 K
B. 31.5 K
C. 43.7 K
D. 53.4 K

Answer

C

Explanation

At equilibrium `Delta G= 0`
`Delta H- T Delta S= 0`
`T= (Delta H)/(Delta S)= (-743.1)/(-17) = 43.7K`