question_answer

Diborane is a potential rocket fuel which undergoes combustion according to the equation \[{{B}_{2}}{{H}_{6}}(g)+3{{O}_{2}}\xrightarrow{{}}\,{{B}_{2}}{{O}_{3}}(s)+3{{H}_{2}}O(g)\]

Calculate the enthalpy change for the combustion of diborane in kJ/mol. Given

(i)\[2B(s)+\frac{3}{2}{{O}_{2}}(g)\xrightarrow{{}}{{B}_{2}}{{O}_{3}}(s);\,\,\Delta H=-1273\,\,kJ\,\,per\,\,mol\]

(ii) \[{{H}_{2}}(g)+\frac{1}{2}{{O}_{2}}(g)\xrightarrow{{}}{{H}_{2}}O(l);\,\,\Delta H=-\,286\,\,kJ\,per\,mol\]

(iii) \[{{H}_{2}}O(l)\xrightarrow{{}}\,{{H}_{2}}O(l);\,\,\Delta H=44\,\,kJ\,per\,mol\]

(iv) \[2B(s)+3{{H}_{2}}(g)\xrightarrow{{}}{{B}_{2}}{{H}_{6}}(g);\,\,\Delta H=36\,\,kJ\,per\,mol\]

Answer:

(-2035)