B.Sc

For your reference I'm sharing this link blogged by Shiksha. These are not IIT colleges but then the other colleges best for B.Sc degree.
https://www.google.co.in/url?sa=t&source=web&rct=j&url=https://www.shiksha.com/science/articles/top-10-bsc-msc-colleges-in-india-blogId-13473&ved=0ahUKEwjj-s3Li6nWAhWINY8KHbydBrIQFgjCATAA&usg=AFQjCNER5VXBrUZKa_MmDG0ryP3AzAcmUw

You can do M.Sc or you can do MBA, which is best nowadays for good placement.

You can get 2-2.8 LPA.

What do you want to pursue? Since you want to do UG, you can shortlist the universities you wish to apply to and the courses you want to study. Take SAT and TOEFL early so that you are prepared for the next steps of the application.

MS Computer Science in German universities is offered as engineering PG degree. You are not eligible for MS Computer Science as you have completed only 10+2+3 years education against requirement of 10+2+4 years of education for seeking admission in MS in German Universities.

There are a number of options available to you after completing B.Sc. in Chemistry. Some of the popular courses you can opt for are as follows:
1) MBA
2) M.Sc.
3) MS/M.Tech
4) MCA
5) UPSC (Civil Services)
6) CDS (Defence services)
The choice is yours. You should select a course which you feel comfortable with, as it will stick with you for most of your professional career.

You can appear for CGL and UPSC.