Question

In the reaction:,$S + 3/2O_{2} \rightarrow SO_{3} + 2x$ kcal and $SO_{2} + 1/2O_{2} \rightarrow SO_{3} + y$kcal,

heat of formation of $SO_{2}$is

• A. (x+y)
• B. (x –y)
• C. (2x + y)
• D. (2x –y)

Answer 1

Answer: (D)

(2x –y)

Answer 2

: $S + 3/2O_{2} \rightarrow SO_{3} + 2xkcal$ …(i)

$SO_{2} + 1/2O_{2} \rightarrow SO_{3} + ykcal$ …(ii)

Now, subtract eq. (ii) from (i), we get,

$S + O_{2} \rightarrow SO_{2} + 2x - ykcal$

$\therefore$Heat of formation of $SO_{2}$in equal to 2x – y kcal.