Question

The heat of formation of \( \text{SO}_2(g) \) is given by: $$ S(g) + \frac{3}{2} O_2(g) \rightarrow SO_3(g) + 2x \, \text{kcal} $$ $$ SO_2(g) + \frac{1}{2} O_2(g) \rightarrow SO_3(g) + y \, \text{kcal} $$ 

• A. \( \frac{2x}{y} \, \text{kcal} \)
• B. \( x + y \, \text{kcal} \)
• C. \( y - 2x \, \text{kcal} \)
• D. \( 2x + y \, \text{kcal} \)

Hint:

The heat of formation is calculated using Hess's law, which involves adding or subtracting the enthalpy changes of the given reactions.

Answer 1

The Correct Option is C

The standard heat of formation for \( \text{SO}_2 \) is defined as the enthalpy change upon forming 1 mole of \( \text{SO}_2(g) \) from its constituent elements in their standard states.
Based on the provided reactions, this heat of formation is calculated to be \( y - 2x \).
Final Answer: \( y - 2x \, \text{kcal} \).