`{:(C+O_(2)(g)rarrCO_(2)" ......(i),",DeltaH=-"393 k J mol"^(-1)),(H_(2)+1//2O_(2)rarr H_(2)O", .....(ii)",DeltaH=-"287.3 k J mole"^(-1)),(2CO_(2)+2H_(2)O rarr C_(2)H_(5)OH+2O_(2)" .....(iii)",DeltaH="1366.8 kJ mol"^(-1)):}`
Find the standard enthalpy of formation of `C_(2)H_(5)OH(l)`

Options

A. `"281.1 kJ mol"^(-1)`
B. `-"281.1 kJ mol"^(-1)`
C. `"562.2 kJ mol"^(-1)`
D. `-"562.2 kJ mol"^(-1)`

Answer

B

Explanation

Formation of `C_(2)H_(5)OH,`
`2C+3H_(2)1//2O_(2)rarr C_(2)H_(5)OH`
`eq(1)xx(2)+eq(2) xx(3)+eq.(3)`
`2C+2O_(2) rarr 2CO_(2)`
`3H_(2)+3//2O_(2) rarr 3H_(2)O`
`3CO_(3)+2H_(2)O rarr 3H_(2)O`
`3C+3H_(2)+1//2O_(2)rarr C_(2)H_(5)OH+#O_(2)`
`=-394xx2-289.3xx3+1366.8`
`=-"281.1 kJ/mole"`