(i) NF3 is an exothermic compound whereas NCl3 is not.
(ii) F2 is most reactive of all the four common halogens.
(b) Complete the following chemical equations:
(i) C + H2SO4 (conc.)-->
(ii) P4 + NaOH + H2O-->
(iii) Cl2+F2 ------>
(excess)
(i) As we move down the group 17, the size of the atom increases from fluorine to chlorine. The larger difference in the size of N and Cl results in the weakness of strength of N-Cl bond.
On the other hand, the difference in size of N and F is small; consequently, the N-F bond is quite strong. As a result, NF3 is an exothermic compound.
(ii)
1. F-F bond has low enthalpy because the fluorine atom has a small size and due to their small size, there is repulsion between two atoms making its bond enthalpy lower, hence more reactivity is more.
2. It has a small size and high charge density due to which it is the most electronegative element.
