If $38 \cdot 55 \mathrm{~kJ}$ of heat is absorbed when $6 \cdot 0 \mathrm{~g}$ of $\mathrm{O}_{2}$ react…

If $38 \cdot 55 \mathrm{~kJ}$ of heat is absorbed when $6 \cdot 0 \mathrm{~g}$ of $\mathrm{O}_{2}$ react with CIF according to reaction $2 \mathrm{CIF}_{(\mathrm{g})}+\mathrm{O}_{2(\mathrm{~g})} \longrightarrow \mathrm{Cl}_{2} \mathrm{O}_{(\mathrm{g})}+0 \mathrm{~F}_{2}(\mathrm{~g})$ What is the standard enthalpy of reaction?
  1. $72.28 \mathrm{kJ}$
  2. $205.6 \mathrm{kJ}$
  3. $102.8 \mathrm{kJ}$
  4. $49.80 \mathrm{kJ}$

Solution

$\begin{array}{l} 2 \mathrm{ClF}_{(\mathrm{g})}+\mathrm{O}_{2(\mathrm{~g})} \longrightarrow \mathrm{Cl}_{2} \mathrm{O}_{(\mathrm{g})}+\mathrm{OF}_{2(\mathrm{~g})} \\ \text { For } 6.0 \mathrm{~g} \text { of } \mathrm{O}_{2} \Rightarrow \Delta \mathrm{H}=+38.55 \mathrm{~kJ} \\ \therefore \text { For } 32.0 \mathrm{~g} \text { of } \mathrm{O}_{2} \Rightarrow \Delta \mathrm{H}^{0}=\frac{38.55 \times 32}{6}=205.6 \mathrm{~kJ} \end{array}$

Asked in: MHT CET 2020 (16 Oct Shift 1)

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