Dear Khaing,

The following gives a concise summary of E1, E2, SN1 and SN2:

http://www.freelance-teacher.com/organic_chemistry_sn2_sn1_e2_e1.pdf

I have attached the pdf file to this message.

Hoping this will be helpful,

Rafik

Thank you very much Dr Karaman and Dr Okoli for your kind help and time.