IIT

You can apply to NITs through JEE Mains 3 times.
You can apply to IITs through JEE Advanced 2 times.

By just crossing the cutoff you will not get any seat in IIT's, you need to score 30-40 marks higher than the cutoff to get any seat in any IIT's.

No you need to apply for JEE Mains and then advance and get good rank and on the basis of 12th class you can get a seat in IIT.

You need to score a minimum of 50% in class 10th.

Hello Rambabu,
Yes, it's the best. You can study for JEE Mains as well as clearing your backlogs simultaneously. Take some tuition or join some class for this to happen successfully.

You are eligible to seek admission in IITs and NITs in Post graduation degrees by appearing in JAM examination conducted by IITs after B.Sc. IITs have a requirement that for seeking admission in M.Sc Chemistry candidate must have had Maths as a subject in 10+2 and chemistry as a subject in all six semester of B.Sc.

Hello Parteek,
For appearing there is no problem as you are paying for this but for getting admission you have to fulfil the eligibility criteria.

Hello Manoj,
You have said that you have scored 69 marks out of 360 in JEE Mains. What went wrong? Can you analyse & take corrective action? I am attaching a link that will predict college for you.
https://www.resonance.ac.in/reso/news/JEE-Main-Branch-Predictor.aspx

You can only get into IITs after clearing JEE Advanced and JEE Advanced is tougher than JEE Mains. You have got 55 marks out of 360. No government college will give you admission at such score. However, you can get into private colleges.

IIT needs JEE Advanced & IIIT needs JEE Mains scores. Both have different prospects so are the ranks required. For JEE Advanced, you need less than 7-8K CRL, but for IIIT, your chance is nearly nil at 25K.