Singing this Note is IMPOSSIBLE!

I think you've discovered the difference between "chest voice" and "head voice".  Usually amateur singers have a break between the two.  Trained singers can make that break either nonexistent or very small.
Here's the theory: an amateur singer is NOT tuning their vocal tract resonant frequency to the note they are singing.  When they sing lower notes (chest voice), their vocal folds are vibrating slower than the resonant frequency of their vocal tract.  When they sing higher (head voice), their vocal folds are vibrating faster than the resonant frequency of their vocal tract.  They break when their vocal folds are at the same frequency as the vocal tract.
There are two strategies a trained singer could use to avoid this break.
First, they might change the resonant frequency of their vocal tract dynamically, so that as they switch notes from chest to head voice, they quickly drop the resonant frequency of their vocal tract to avoid getting the two at the same frequency.
A different and perhaps superior strategy would require changing both ends of the vocal tract, which will require not just using your mouth to alter the top end but also using your chest muscles to alter the bottom end.  A resonant standing wave in the vocal tract will have nodes -- places where the pressure or velocity amplitude is zero.  If one of those velocity nodes is where the vocal folds are, there is no way to couple energy from the vocal fold into sound.  That's why you can't sing the note.  But if you get the zero-pressure maximum-velocity node on top of the vocal fold, you get maximum energy coupling.  I suspect that well trained singers have learned to dynamically alter their vocal tract to line up a max-velocity node on their vocal folds at all notes, eliminating the problem of the break between chest and voice entirely.