Hello! I am currently a sophomore in high school and I was just wondering about the benefits of taking AP tests.
Could anyone tell me which AP tests are the hardest to score well on (based on statistics or personal experience) or rank them? Also, which tests are particularly impressive to colleges if you score well on them?
I appreciate any help! Thank you 
For starters, you could get college credit and/or place out of intro courses
This has been asked and answered sooooo many times, but IMO,
The hardest and/or most-time consuming are: Calc BC (if taught as a one-year course after pre-calc), Physics C E&M
A small step down to the next level: Physics C Mech, Bio, Chem
A small step down to the next level: Eng Lit, Eng Lang, USH, Spanish Lit
A small step down to the next level: World Hist, Euro Hist, Art Hist, Calc AB, Calc BC (if taught as a one-year class after Calc AB)
A HUGE leap down to the next level: everything else
Don’t have that mind-set. Take classes that interest and challenge you without thinking about what some anonymous AO may or may not think. FWIW, while your AP scores may be used by admissions to validate the rigor of your course (i.e. an A in the course and a 4 or 5 on the exam is fine; and A and a 1 or 2 on the exam may lead to questions of grade inflation), AP scores have is little other benefit in the admissions process IMO
Are you saying that all the Foreign Language exams are on the same level as Stats or Environmental Science?
No colleges really care about what AP tests you take. As long as your schedule is rigorous enough (for whatever college(s) you want to apply to) and your AP scores can back up your grades, they’re not gonna start drooling over a 5 in AP French vs. a 5 in AP Statistics.
In terms of difficulty of the exams, yes, I am saying that. AP language exams do not test to that high a level; they’re testing to approx the low-intermediate level. As I stated originally, it’s my opinion, others may think differently.
As a student who has taken 18 AP exams, I believe the hardest ones are the following:
Physics E&M, Physics 2, Chemistry, European History, Spanish Language, Physics C Mechanics, Biology, AP Language, AP Literature, Physics 1, AP Statistics, AP World, AP Calc BC, AP Calc AB, AP Chinese, AP Psychology, AP Environmental, and AP Human Geography.
And top 5 impressive/important ones are the following:
AP Chemistry, AP Physics E&M, AP Calc BC, AP Biology, and AP Language.
And yes, I’m a high school senior who barely missed AP State Scholar for getting 6 4’s… ;(
*People tell that AP Scores don’t matter for college admission, but they in fact do. How do I know? My father is an admission officer.