Question

$N{F}_3$ is an exothermic compound but $NC{l}_3$ is endothermic compound.

Answer 1

In case of$N{H}_3$ $N-F$ bond strength is greater than $F-F$ bond strength whereas $N-Cl$ bond strength is ower than $Cl-Cl$ bond strength So the formation of ${NF}_3$ is spontaneous but during the formation of ${NCl}_3$ energy needs to be supplied.Therefore, ${NF}_3$ is an exothermic compound but ${NCl}_3$ is endothermic compound.