Science

I think if you failed while pursuing your graduation, the course start date & end date would say it all. About your job, while you appear for your job interview, you will surely be asked for the reason. Here, I would suggest you to focus on your skill set so much more that you can compensate for your dropped years. That will really be helpful for you. You can trust on this that once you get a good job, nobody will ever ask you for the reason you dropped 2 years of graduation.

You need to have cleared your graduation with 50% marks with mandatory course : B.Sc.
Candidate must have studied at least 2 year (4 semesters) of 3 years degree course in any 2 subjects from the following:
1. Physics
2. Chemistry
3. Biology (Zoology/ Genetics/ Bio-technology/ Physical Anthropology)
The candidate also need to clear IPU CET as the admission is through counseling based on the rank obtained in Guru Gobind Singh Indraprastha University Common Entrance Test (GGSIPU CET).

Please refer to the answer in the link below. https://ask.shiksha.com/hii-sir-i-am-nishvata-fofandi-i-am-in-b-f-sc-in-second-semester-but-i-want-admition-in-b-sc-is-that-possible-qna-5218825.

You can consider following colleges:
1. Andhra University
2. Cochin University of Science and Technology
3. Indian Institute of Technology Delhi
4. Savitribai Phule Pune University

The chemistry of the compounds of carbon covers a wide field, wider than that covered by any other element. Its scope embraces all living matter, as well as the vast number of non-living substances which are produced through the agency of life. Moreover, it includes a very great number of compounds unrelated to life or to living processes which have been built up by the chemist in the laboratory by methods he has devised.

As you have passed HSC with PCB, you have a lot of options to choose from. Some are:
1. B.Sc in Microbiology
2. B.Sc in Biotechnology
3. B.Sc in Biochemistry
These three are most trending nowadays. However, lots of other options are also available such as common zoology, botany and others.

Yes, there is a 2-year integrated M.Sc in BITS. Check the BITS website for more details.
All the best.