Science

Hi,
For getting into the BCA course offered by West Bengal colleges, the candidates must have completed their higher secondary from an institution recognised by the higher education board of the state of West Bengal. Yes, some universities provide BCA degree without mathematics in 10+2. But you must be eager to learn math, as BCA course is a Computer Science course and computers are all about math, so it includes math.
Best of luck.

Not so good. The openings for this field of job are very less. You need to get placed from the campus you studied at. It's difficult to find a job outside your campus.

Your percentage is low to have admission in DU regular, but you may try DU SOL.
You'll get a graduate degree. Also, you can do a part-time course which will also add to your biodata. Do some computer course or language course side by side.
In SOL, I will suggest you to pursue B.A. English Hons. After that, you can have a good job in an MNC with a language certificate also.
Hope this helps.

There's a lot of scope, though most of it goes into research work.
If you are into pure science and you're interested in chemistry, go for it. There are various jobs you can get in private as well as public sector, you just you need to be good at your things. Major jobs opportunities are in research and development sector, food industries chemical testing, being a professor, etc.

It's not easy to get a job in a foreign country, always remember that. Ireland, no doubt, has a very good market but the competition is immense, especially for international students. Also for Indians, work permit scheme in the UK is very tough. Check immigration website of Ireland for skilled occupation list or labour shortage list, have an idea of the market demands, apply to a very good university having strong industrial tie-ups. Most importantly, you have to be strong academically.

Please specify the entrance test in which you secured this rank so that I may be able to populate relevant details regarding your eligibility to various colleges. Regards.