Dear,

Surely you can do CA while doing BSC too . But it can be hard because both are two parallel world . In one you have to deal with advance environment laws and their theory via Physics , Chemistry and maths or bio . While in another , you have to go through economic structure , taxation process ,business laws & accounting of different entities .

All in all , CA in itself has a vast syllabus and tough course while BSc can be hard at sometimes too if you study deeply .

Hope this helps!