Question

`DeltaU^(@)` of combustion of methane is `-X kJmol^(-1)`. The value of `DeltaH^(@)` is `:`
(i) `= DeltaU^(@)` (ii) ` gt DeltaU^(@)` (iii) `lt DeltaU^(@)` (iv)` = 0`

Answer 1

The balanced equation for combustion of methane will be
`CH_(4)(g) + 2O_(2)(g) rarr CO_(2)(g) +2H_(2)O(l)`
Thus, `Deltan_(g)= (n_(p) -n_(r))_(g)= 1 -3= -2`
`DeltaH^(@) lt DeltaU^(@) + Deltan_(g) RT = - X - 2RT`
Thus, `DeltaH^(@) lt DeltaU^(@)` . Hence, (iii) is the correct answer.