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Comment on the thermodynamic stability o...

Comment on the thermodynamic stability of NO(g).
Given: `(1)/(2)N_(2)(g)+(1)/(2)O_(2)(g)toNO(g),Delta_(r)H^(0)=90kJ*mol^(-1),NO(g)+(1)/(2)O_(2)(g)toNO_(2)g,Delta_(r)H^(0)=-74kJ*mol^(-1)`.

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For the first reaction, `Delta_(r)H^(0)` refers to the standard enthalpy of formation `(Delta_(f)H^(0))` for NO because 1 mol of NO forms from tis constituent elements. The positive value of `Delta_(f)H^(0)` of a compound implies that the compound has more enthalpy (or energy) than its constituent elements. hence, the compound will be unstable. therefore, the positive value of `Delta_(r)H^(0)` for the first reaction indicates that nO is unstable.
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