Correct Answer - A
दिया है, `1/2X_(2)+1/2Y_(2)to XY,DeltaH==-200` किलोजूल
माना की `X_(2), Y_(2)` तथा XY की वियोजन उर्जाये है ---
`a,a/2,a` ( अनुपात दिया है | )
`X_(2)to2X," "DeltaH=a" "…(2)`
`Y_(2)to2Y," "DeltaH=a/2" "...(2)`
`XYtoX+Y," "DeltaH=-a" "...(3)`
समीकरण `(1)+(2)-2xx(3)` से,
`DeltaH=a+a/2-2a=-a/2`
या `1/2X_(2)+1/2Y_(2)toXY,`
`DeltaH=a/2+a/4-a=-a/4`
`:." "-a/4=-200`
`:." "a=800` किलोजूल मोल`""^-1 `