Hello Aakanksha
You will have to study mathematics in the first year because it is a compulsory subject for B.Tech.
As far as your desire of studying Chemistry is concerned, I would suggest you to go for Chemical engineering.

Whichever field you choose, if you're aiming to become an engineer it's necessary to have a grip on math as well. As far as the field is concerned, you could become a chemical engineer where the chemistry would be your subject of interest, but keep in mind that you'll still have to do math.