question_answer

Calculate the heat of formation of \[PC{{l}_{5}}(s)\] from the following data \[2P(s)+3C{{l}_{2}}(g)\,\,\to \,\,2PC{{l}_{3}}(l);\,\Delta H=-151.8\,kcal\] \[PC{{l}_{3}}(l)+C{{l}_{2}}(g)\,\,\to \,\,PC{{l}_{5}}(s);\,\,\Delta H=-32.8\,kcal\]                 [JIPMER 1999]

A)                 ? 108.7 kcal        

B)                 + 108.7 kcal

C)                 ? 184.6 kcal

D)                 + 184.6 kcal