Question

If \( \text{C}(s) + \text{O}_2(g) \rightleftharpoons \text{CO}_2(g) \), \( \Delta H = R \) and \[ \text{CO}(g) + \frac{1}{2} \text{O}_2(g) \rightleftharpoons \text{CO}_2(g), \quad \Delta H = S \] then heat of formation of CO is:

• A. R + S
• B. R - S
• C. R x S
• D. S - R

Hint:

Hess's law allows us to calculate the heat of formation by adding or subtracting known enthalpy changes.

Answer 1

The Correct Option is B

The heat of formation of CO can be derived from Hess's Law, by adding and subtracting the enthalpy changes of the reactions. The result is \( R - S \).

Step 2: Conclusion.
Thus, the correct answer is \( R - S \).