Chemical reactions are invariably associated with the transfer of energy either in the form of hear or light. In the laboratory, heat changes in physical and chemical processes are measured with an instrument called calorimeter. Heat change in the process is calculated as: q= ms `Delta T`, s= Specific heat = `c Delta T`= Heat capacity. Heat of reaction at constant pressure is measured using simple or water calorimeter. `Q_(v)= Delta U`= Internal energy change, `Q_(P) = DeltaH, Q_(P) = Q_(V) + P Delta V and DeltaH = Delta U+ Delta nRT`. The amount of energy released during a chemical change depends on the physical state of reactants and products, the condition of pressure, temperature and volume at which the reaction is carried out. The variation of heat of reaction with temperature and pressure is given by Kirchoff's equation: `(DeltaH_(2) - DeltaH_(1))/(T_(2)-T_(1))= Delta C_(P)` (At constant pressure), `(DeltaU_(2) - DeltaU_(1))/(T_(2)-T_(1)) = DeltaC_(V)` (At constant volume)
The specific heat of `I_(2)` in vapoour and solid state are 0.031 and 0.055 cal/g respectively. The heat of sublimation of iodine at `200^(@)C` is 6.096 kcal `mol^(-1)`. The heat of sublimation of iodine at `250^(0)C` will be

Options

A. `3.8 "k cal" mol^(-1)`
B. `4.8 "k cal" mol^(-1)`
C. `2.28 "k cal" mol^(-1)`
D. `5.8 "k cal" mol^(-1)`

Answer

D