1. Tardigrade
  2. Question
  3. Chemistry
  4. The standard enthalpy of formation of H 2(g) and Cl 2(g) and HCl (g) are 218 kJ / mol, 121.68 kJ / mol and 92.31 kJ / mol respectively. Calculate standard enthalpy change in k J for (1/2) H2(g), (1/2) C l2(g) arrow H C l(g)

Question Error Report

Thank you for reporting, we will resolve it shortly

Back to Question

Q. The standard enthalpy of formation of $H _{2}(g)$ and $Cl _{2}(g)$ and $HCl _{(g)}$ are $218\, kJ / mol,\, 121.68\, kJ / mol$ and $92.31\, kJ / mol$ respectively. Calculate standard enthalpy change in $k J$ for $\frac{1}{2} H_{2}(g), \frac{1}{2} C l_{2}(g) \rightarrow H C l_{(g)}$

J & K CETJ & K CET 2010Thermodynamics

Solution:

For reaction, $\frac{1}{2} H _{2}(g)+\frac{1}{2} Cl _{2}(g) \rightarrow HCl (g)$
$\Delta H =\Delta H _{f}( HCl )$
$-\left[\frac{1}{2} \times \Delta H _{f}\left( H _{2}\right)+\frac{1}{2} \times \Delta H _{f}\left( Cl _{2}\right)\right]$
$=-92.31-\left[\frac{1}{2} \times(218)+\frac{1}{2} \times(121.68)\right]$
$=-262.15\, kJ$