Question

state the rules to determine the location of primary stress in the word economical

Answer 1

Well Stress Marking doesn't have any universal rules but here are some stated by BIEAP,in their grammar book.
Note:These are not applicable for every word.

Rule1:words ending with self,ee,eer,ette,ique have stress at last syllable.
Rule 2:Words ending with ion,ial,ic,ious,eous have stress at second last syllable.
Rule 3:Words ending with ical,ian,ize,ity,logy,graphy have stress at third last syllable.
Rule 4:Words ending with silent 'r' sound have stress at first syllable.
And GENERALLY (mostly) noun has stress at first syllable and verb at second syllable. If you have any doubts,ping me at my account or comment box.