Dear Vijay, you haven't mentioned if this is for JEE Mains or NEET. So we shall help you with JEE preparation tips. Do let us know if this is for another entrance examination please. Chemical Bonding and Molecular Structure, Bio-molecules, Polymer, Aldehyde Ketone and Carboxylic acids, Equilibrium, Coordinate Compounds etc. constitute the major part of the Chemistry paper. It is further added that Qualitative Analysis, General principles and Processes of Isolation of Elements and Surface Chemistry etc. have lesser number of questions in the exam. If you can memorise the periodic table, chemical formula of each gas and their structure, Chemistry can be easier for you. Focus on focus on Organic Compounds containing Oxygen, Equilibrium, Basic Concepts, and Chemical Bonding and Molecular Structure.

Hey there

Ofcourse you can but a score like 70 needs real dedication towards the subject. Now there are various concepts in JEE syllabus which CBSE do not mention in NCERT like r-s configuration etc so you can understand why coaching is important but there are lots of lectures on YouTube you can take help of them.

Good luck