15 days is very less time to crack engineering exams. If you have strong concepts and fundamentals then you can easily crack it. Make sure you have completed your NCERT book. Refer previous year papers to know the level of questions asked in the exam. Practice as much as you can. Solve complete mock test series to work on time management and to analyze your preparation level. Work on your strength and weakness. Focus on the important topics in the exam. Give importance to the topics which carries more weight-age in the exam. You can also solve MCQs related to them. You should daily revise inorganic chemistry as well. Revision plays a good role in fetching good marks. Make sure you revise the syllabus properly. Revise all the formula as well. All the best for your preparation!!