Can you please tell me which sentence is the best choice in terms of grammar. I presume that the third sentence is impossible but I am not able to find out the reason
1. Is it possible to meet you tomorrow?
2. Is to meet you tomorrow possible?
3. Is there to meet you tomorrow possible?
Converting back to statements, and removing the time word "tomorrow" may clarify:
It is possible to meet you.
To meet you is possible.
There is to meet you possible. **
The first one is good English. It uses the dummy subject, an adjective "possible" and the infinitive phrase to complete the predicate "possible to meet you"
The second is poor English. The infinitive in the subject is clumsy. "Meeting you would be possible" is a better sentence.
The third is not correct English. The phrase "to meet you" doesn't appear as the complement of "possible". The expression "There is" should be followed by a noun phrase. You could use "possibility" in the form "There is a possibility of meeting you". Which is correct, but rather long-winded.
You could say "May I meet you tomorrow?", and it would be simpler.
But, if you want to use a construction with the infinitive verb, and ask whether it is possible, then sentence #1 is the only acceptable one.
The construction in sentence #2 would be OK to ask about the possibility of a simple thing: "Is a meeting possible?" , but the whole infinitive verb-phrase, "to meet you tomorrow" is just too long to fit in there gracefully (without sounding awkward).
This is why we use the dummy pronoun or placeholder pronoun "it": "Is it possible to meet you tomorrow?" It simplifies the main sentence to: "Is it possible?", and follows up with the definition of "it" at the end.
Sentence #3 also uses a dummy/placeholder, "there". "There" is similar to "it" but you use "there" only to inquire about the existence of something. "Is there a possibility?" [Does a possibility exist?]
So you could also say, "Is there a possibility to meet you tomorrow?", but the nicest sounding question is #1.
