how can i study organic chemistry last 1 month??????

Primarily study the basic chapters like Haloalkanes and Haloarenes, Alcohols,Phenols and Ethers and Aldehydes Ketones and carboxylic acid chapter. You may be aware that most of the chemical reaction, its preparation properties and uses repeated in remaining lessons. If you are perfect in mentioned lessons in 20 days then you deffinatly can easily study the other chapters. In last chapters I.e.., polymers and chemistry in everyday life you can read only important question which appears for exams. In organic chemistry it is important to learn all basic preparation method like cumene process, Gabrial synthesis, Williamson ether synthesis, Cannizaro`s reaction etc.. Concentrate on these areas so that other area like uses properties can be revised easily within a weak and learn according to weightage of the lessons given by CBSE/or any State board.