Hi

First of all there's no 75% requirement to be eligible for jee main, it's only to be eligible for NITs, IIITs & CFTIs but even for these this year it's not there.

For your reference,

Jee main eligibility criteria is given below-

---------------------------) Qualification required :- to be eligible  for JEE mains you need 10+2/equivalent qualification from a recognised board.

-------------------------) Passing year :- one is eligible for JEE main examination for consecutive three years starting from the year of appearing for 12th /equivalent examination i. e to be eligible  for JEE mains 2022 you should be either appearing for 12th board exam or equivalent  in 2022 or should have passed it in 2021 or 2020

-------------------------) There is no age limit to be eligible

- ------------------------) there is no minimum percentage requirement to be eligible for JEE Main for BE /Btech.

But yes,

To be eligible for BE/BTech  in NITs, IIITs, CFTIs one needs at least 75% marks in class 12th if belongs to General or OBC category  or at least 65% marks in class 12th if belongs to Sc or St category or needs to be in top 20 percentile of their board examination.

5 Subjects to be considered for calculating aggregate percentage are :-

• *Physics

• * Chemistry/biology/biotechnology/Technical Vocational subject.

• *Mathematics

• *A language

• *Any subject other than listed above

So, yes you can replace chemistry by your optional subject provided your optional subject is biology/biotechnology/Technical Vocational subject otherwise you can't replace.

IMPORTANT NOTE :-  This minimum percentage barrier of 75 % - 65% for NITs, IIITs, CFTIs  has been lifted off for jee main 2022 . It means to be eligible all you need to be eligible is to have at least passed 12th .

For detailed information about jee main eligibility criteria  go through our page, the link for which is provided below

https://engineering.careers360.com/articles/jee-main-eligibility-criteria

Thank you