`Delta H_(1)^(@)` for `CO_(2)(g)`, `CO(g)` and `H_(2)O(g)` are `-393.5,-110.5` and `-241.8 kJ mol^(-1)` respectively. Standard enthalpy change for the reaction
`CO_(2)(g)+H_(2)(g) rarr CO(g) + H_(2)O(g)` is

Options

A. `524.1`
B. `41.2`
C. `-265.5`
D. `-41.2`

Answer

B

Explanation

` Delta H = sum [ Delta H _ f ^@ ` products ] - ` sum [ Delta H _ f ^(@) "reactants" ] `
` Delta H ^ @ = [ Delta H _ f ^@ ( CO ) ( g ) + Delta H _ f^ @ ( H _ 2 O ) ( g ) ] - [ Delta H _ f ^@ (CO _ 2 ) ( g ) +Delta H _ f ^@ ( H _ 2 ) ( g ) ] `
` = [ - 110.5 + ( - 241.8 ) ] - [ - 393.5 + 0 ] `
` = 41.2 `