Please show work of Physical Chemistry: Estimate the value of P for the harpoon reaction between…

Please show work of Physical Chemistry: Estimate the value of P
for the harpoon reaction between K and Cl2 for which I = 420
kJ/mol, Ea = 250 kJ/mol, radius atom K = 0,24 nm, and radius
molecule Br2 = 228 pm, d = 400 pm.
Answer key : P = 4.2