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

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

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

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 occup