Consider the following equations.

     ${\text{2Fe(s)}} + {\text{1}}\frac{1}{2}{{\text{O}}_{\text{2}}}{\text{(g)}} \to {\text{F}}{{\text{e}}_{\text{2}}}{{\text{O}}_{\text{3}}}{\text{(s) }}$     $\Delta {{\text{H}}^\Theta } = x$

     ${\text{CO(g)}} + \frac{1}{2}{{\text{O}}_{\text{2}}}{\text{(g)}} \to {\text{C}}{{\text{O}}_{\text{2}}}{\text{(g)}}$     $\Delta {{\text{H}}^\Theta } = y$

What is the enthalpy change of the reaction below?

$${\text{F}}{{\text{e}}_{\text{2}}}{{\text{O}}_{\text{3}}}{\text{(s)}} + {\text{3CO(g)}} \to {\text{3C}}{{\text{O}}_{\text{2}}}{\text{(g)}} + {\text{2Fe(s)}}$$

A.     $3y - x$

B.     $3y + x$

C.     $- 3y - x$

D.     $- 3y + x$

A

This question was answered correctly by nearly 85% of the candidates which was encouraging.