My Major interest is to Major in Chemistry
No matter which common application question you choose, don’t write about what you plan on majoring in. Let’s say you want to be a Chemistry major. (My homage to Heisenberg and Breaking Bad) Your resume is filled with AP Chemistry, internships and summer programs in chemistry, chemistry clubs, etc. And now you write that your interest in Chemistry or how you solved a problem in your chemistry lab, etc, etc .....
You appear one-dimensional. You don’t look like a well-rounded person with multiple interests, perspectives, etc.
And there is yet another great reason to not do this...Most colleges have supplemental essays….one of which asks why this major. If your main essay is about your major….what will you write for the supplemental essay? It will appear repetitive and further promote you as a one-dimensional person.