give equations showing the commercial methods for preparations of the halogen (F2, Cl2, Br2, I2)

Answer 1

Your best bet for these is to google "preparation x commercially". Here is a link for Cl2.
http://en.wikipedia.org/wiki/Chlorine_production
I have noticed over the last few days that your questions contain no noticeable show of work on your part. It appears you are typing questions from some source and I'm answering most of them. That isn't the way this board is supposed to work. This is the end of the freebies. Please show your work on future posts OR explain very fully exactly what you don't understand about a process. Then we can try to help.