Question

Calculate H for the process Hg2Cl2 ? 2Hg + Cl2 from the following information:
Hg + Cl2 --> HgCl2 H = -224kJ
Hg + Hgcl2 --> Hg2Cl2 H =-41.2 kJ

Answer 1

Answer:

The enthalpy of the reaction of the reaction asked in the question is 265.2 kJ.

Explanation:

$Hg + Cl_2\rightarrow HgCl_2,\Delta H_1 = -224kJ$...(1)

$Hg + HgCl_2\rightarrow Hg_2Cl_2,\Delta H_2 = -41.2kJ$..(2)

$Hg_2Cl_2\rightarrow 2Hg + Cl_2,\Delta H_3=?$...(3)

(1)+(2)

$\Delta H_4=-224kJ+(-41.2kJ)= -265.2 kJ$

$2Hg+Cl_2\rightarrow Hg_2Cl_2,\Delta H_4=-265.2 kJ$...(4)

On reversing the equation (4)we get (3):

$\Delta H_4=-265.2 kJ =-(\Delta H_3)$

$Hg_2Cl_2\rightarrow 2Hg+Cl_2,\Delta H_3=265.2 kJ$

The enthalpy of the reaction of the reaction asked in the question is 265.2 kJ.