CO(g) + H\(_2\) O\(_{(g)}\) → CO\(_{2(g)}\) + H\(_{2(g)}\)
Calculate the standard heat change of the reaction above, if the standard enthalpies of formation of CO\(_{2(g)}\), H\(_2\)O\(_{(g)}\) and CO\(_{(g)}\) in kJmol\(^{-1}\) are - 394, -242 and - 110 respectively.

A.

+ 262 KJ mol -1

B.

- 262 KJ mol -1

C.

+ 42 KJ mol -1

D.

- 42 KJ mol -1

Correct answer is D

\(\Delta H (formation) (CO_2) = -394\)

\(\Delta H (formation) (H_2 O) = -242\)

\(\Delta H (formation) (CO) = -110\)

\(X = \sum H_{P} ^{F} - \sum H_{R} ^{F}\)

= (-394+ 0) - (-110 - 242 )

= -394 +352

= - 42 kJmol\(^{-1}\)