The Total solution for NCERT class 6-12
Comment on the thermodynamic stability of NO(g),┬аgiven
N2(g)┬а+┬аO2(g)┬атЖТ NO(g)┬а; ╬ФrH╬╕┬а= 90 kJ molтАУ1
NO(g)┬а+O2(g)┬атЖТ NO2(g)┬а: ╬ФrH╬╕= тАУ74 kJ molтАУ1
The positive value of ╬ФrH┬аindicates that heatis absorbed during the formation of NO(g). This means that NO(g)┬аhas higher energythan the reactants (N2┬аand O2). Hence, NO(g)┬аis unstable.
The negative value of ╬ФrH┬аindicates that heatis evolved during the formation of NO2(g)┬аfrom NO(g)┬аand O2(g). The product, NO2(g)┬аis stabilized withminimum energy.
Hence,unstable NO(g)┬аchanges to stable NO2(g).