When 1.0 g of oxalic acid `(H_(2)C_(2)O_(4))` is burnt in a bomb calorimeter whose capacity is 8.75 KJ/K, the temperature increases by 0.312 K, the enthalpy of combustion of oxalic acid at`27^(@)C` is :

Options

A. `-245.7kJ//mol`
B. `-244.452kJ//mol`
C. `-241.5kJ//mol`
D. None of these

Answer

D

Explanation

`H_(2)C_(2)O_(4)(l)+(1)/(2)O_(2)(g)rarrH_(2)O(l)+2CO_(2)(g)`,
`Deltan_(g)=3//2`
`DeltaU_(c )=-(0.312xx8.75)/(1)xx90`
=-245.7 kJ/mol
`DeltaH=DeltaU+Deltan_(g)RT`
`=-245.7 +(3)/(2)xx(8.314xx300)/(1000)`
=-241.95 kJ/mol