Science

Yes, you can do it. Science is one of the streams in class 11th which the students have to take up once they successfully pass out of their Class 10th. It mainly consists of the subjects : Physics, Chemistry and Mathematics. Biology is also an option which can be taken in the Medical Stream. Now once you pass out of your Class 12th with the Science stream, you are eligible to take up graduation in any stream except medical (If you have not studied Biology). So if you take up B.Sc. Physics/Chemistry/Maths, this would be considered as the degree in Science stream/subjects. But coming to the B.Tech thing, it is Bachelors in Technology. This is also a Science background graduation programme, but the Degree in Science cannot be considered equal to the degree in B.Tech
B.Sc is of 3 years but B.Tech is of 4 years. Also B.Sc. Is a Science graduation, but B.Tech is a technical course. So B.Tech is more valued.

I'll try to put a better answer. I think this question must be raised in every mind before becoming a part of any B.Sc. batch at BHU. One thing is very common in students enrolled in B.Sc.(Hons) at BHU, That all have prepared for Medical/Engineering entrance examinations. The worst thing with these guys is, they often don't know what is the difference between science and engineering/medical. Scope in any subject and the possibility of employment through the subject are two different topics. Therefore, before getting admission in B.Sc. at BHU, it is very important to know what you want to get through B.Sc. and what you want to do after B.Sc.(Hons.). Once this decision is made, the next thing is to get yourself out of the inferiority complex. What kind of inferiority complex ? So don't compare yourself/your courses/your Institute of science with other programs (B.Tech. B.E. )/premier Institute like IITs and others. As a student of the Institute of Science, you have an identity and characteristics.
Now come to the point. I dont know the subject( and subjects combination) you are going to choose as your Hons. Therefore I am going to explore all possibilities. Since I dont have any experience in Bio group so here I can answer only for B.Sc.(Hons) Maths group.
Let there is no any subject of your interest and not looking for research(or career in academics), your maths is above average and you are only seeking a job. Then you can-
1)- Choose Statistics as your Hons subject (with subject combination Math-Stat-CS or Math-Phy-Stat). Done you B.Sc. Stat > Write JAM/ISI Entrance/BHUPET >Get Admission in M.Sc./M.Stat. at IITK/IITB/ISI/BHU > Get Placed in any relevant profile after completing your PG degree. You can also write for Indian Statistical Services exam organized by UPSC every year.
2)- Choose Chemistry Hons(Subject Combination PMC ). Done your B.Sc. Chemistry. Write JAM/BHUPET>Get admission in M.Sc. at IITs/BHU> try to Get Placed in any relevant profile after completing your PG degree. In the last semester of MSc, You can also write GATE, using GATE score you may be placed at PSUs like ONGC and other. Gate score can also be used for BARC recruitment of Scientific Officer. Apart from this, you can also try for chemist exam organized by UPSC every year. If you dont want to go for masters, you can find many job profiles for which a chemistry graduate is required.

At present, the college website does not shown the eligibility criteria of the asked course. However, on the basis of other colleges eligibility criteria, you can do the PGD in Nutrition and Dietetics at St. Ann's College for Women. The eligibility criteria is given below.
Eligibility criteria : Pass with 60% aggregate marks in Bachelors of Science Degree (Home Science or Medical or Non-Medical or Bio sciences or Medical Science and Allied Medical or Nutrition and Dietetics or Food Technology) or Veterinary Microbiology and Parasitology or Genetic Engineering and Biotechnology or Clinical Chemistry or Public Health and Allied Sciences or equivalent,