B.Sc

You have to score good marks in class 12th boards, so that you get admission in DU. If not so good, then you have to appear in exam conducted by BHU, Allahabad University, or many other national importance college.

Yes, you can apply for an entrance exam conducted by ICAR for pursuing M.Sc. After qualifying the exam, you manage to get seat according to merit.

There are various job opportunities in this field like Food Scientist, Food Technologist, Food Chemist, Product Development Specialist, Food Chemist, Food Inspector, Toxicologist, Process Development Specialist, Manufacturing Specialist, Food Production Manager, Sales, Marketing & Brand Management & Dietician, Nutritionist, Animal Nutritionist, and Diet & Fitness Counselor.

Apart from M.Sc, certification courses can also be one option for the B.Sc Chemistry graduates e.g. Post-Graduate Diploma in Analytical Chemistry (PGDAC). After B.Sc Chemistry, you can search for jobs in chemical industries, pharmaceutical companies, industrial units, etc. However, I would suggest that you should pursue M.sc in Chemistry.

For Pursuing B.Sc (hons), science stream in class 12th is must for the candidates.

There are many options available for you, after you complete (B.Sc honors) in Computer science. Some of the options available before you are as follows:
Call Centers
Computer-Aided Design
Computer Science Engineer
Hardware Engineer
Network Engineer
Software Engineer
Web Designer
Web Developer