There are 2 US states that have no common border with any other state. These are Alaska and Hawaii. The remaining states are collectively considered the 48 "lower" or "contiguous" states. (Alaska would be considered the 49th continental state.)
Hawaii is an island, and Alaska has a land border only with Canada, which is a different country.
Two
48.
48 states border at least one other state.
49 hawwaii all by them self.
5
chicago
12
there are 4 states where India share boundary with china
4
It depends. The two states border each other, so the shortest distance between them is zero miles at the border.
There are three: United States, Belize and Guatemala.
Too many to name them all, twelve in the US north and four in the south.