Tell me please if these two phrases mean the same in the following sentence.
Kate, we are going to to pop in for an hour. Is it OK with/to you.
Most of the time I hear native speakers use the preposition with in the phrase, but I feel that the preposition to is fine too.
(This answer is from the viewpoint of a northeastern US English speaker. Other dialects may have different answers.)
In this case only with is really idiomatic. "OK with you" means you find it good, or you don't have a problem with it. "OK to you" means something more like "behaving acceptably towards you".
But the confusion might come from the fact that there are many constructions where you would say "OK to you". For example, "Does that look OK to you?" But that's part of the construction "to look X to Y", meaning "to appear to Y have an X nature".
Informally, I've also heard people say "Is that OK by you?" or "Is that OK for you?" so you have a wide range of choices!
The preposition "to" expresses direction. So in your example it is not really apt because it would imply your treatment of the other person. You would in effect be asking if your decision to go to the shops treated your friend fairly.
It is more appropriate in this instance to say "okay with you".
