InterviewSolution
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InterviewSolution
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The standard heat of combustion of a solid boron is equal to:A. `DeltaH_(f)^(@)(B_(2)O_(3))`B. `1//2DeltaH_(f)^(@)(B_(2)O_(3))`C. `2DeltaH_(f)^(@)(B_(2)O_(3))`D. `1//2DeltaH_(f)^(@)(B_(2)O_(3))` |
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Answer» Correct Answer - B Combustion reaction of solid boron `B(s)+(3)/(4)O_(2)(g)rarr(1)/(2)B_(2)O_(3)(s)` `Delta H_(r )^(o)=Delta H_(c )^(o)=(1)/(2)DeltaH_(f)^(o)(B_(2)O_(3),s)-Delta H_(f)^(o)(B,s)-(3)/(4)Delta H_(f)^(o)(O_(2),g)` `Delta H_(f)^(o)` of element in stable state of aggregation is assumed to be zero. `DeltaH_(c )^(@)=(1)/(2)Delta H_(f)^(o)(B_(2)O_(3),s)` |
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