Question
Two reactions are given below :
$$\eqalign{
& \left( {\text{i}} \right)C{O_{\left( g \right)}} + \frac{1}{2}{O_{2\left( g \right)}} \to C{O_{2\left( g \right)}} \cr
& \left( {{\text{ii}}} \right)A{g_2}{O_{\left( s \right)}} \to 2A{g_{\left( s \right)}} + \frac{1}{2}{O_{2\left( g \right)}} \cr} $$
Which of the following statements is true ?
A.
For $$\left( {\text{i}} \right)\Delta H < \Delta U$$ and for $$\left( {{\text{ii}}} \right)\Delta H > \Delta U$$
B.
For $$\left( {\text{i}} \right)\Delta H > \Delta U$$ and for $$\left( {{\text{ii}}} \right)\Delta H < \Delta U$$
C.
For both $$\left( {\text{i}} \right)$$ and $$\left( {{\text{ii}}} \right)\Delta H > \Delta U$$
D.
For both $$\left( {\text{i}} \right)$$ and $$\left( {{\text{ii}}} \right)\Delta H < \Delta U$$
Answer :
For $$\left( {\text{i}} \right)\Delta H < \Delta U$$ and for $$\left( {{\text{ii}}} \right)\Delta H > \Delta U$$
Solution :
$$\eqalign{
& {\text{For}}\,\,\left( {\text{i}} \right),\Delta {n_g} = 1 - \frac{3}{2} = - \frac{1}{2} \cr
& {\text{For}}\left( {{\text{ii}}} \right),\Delta {n_g} = \frac{1}{2} - 0 = \frac{1}{2} \cr} $$