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Is there really any difference between these sentences?

Correct me if I'm wrong but I think they are merely different ways of expressing the same thing.

There are no chairs in ths room. Vs There are no chair in this room.

There isn't a chair in this room. Vs There are not chairs in this room.

Thanks very much indeed.
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Not a very helpful post, shencaixiansheng-- and it is neither well-written nor accurate.

There are no chairs in this room. Vs There is no chair in this room.-- The meanings are the same; the first is the natural utterance unless there has been a previous claim of the presence of a single chair there.'

There isn't a chair in this room. vs There are not any chairs in this room.-- The 2nd (as amended) is again the natural utterance, with the same exception as above.
Comments  
There are no chairs in this room. Vs There is no chair in this room.

There isn't a chair in this room. vs There are not chairs in this room.
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You can have either formal ways of saying that or informal ways of saying that.

formal way: there isn's any chair in this room.

informal ways: anyway you want.
 Mister Micawber's reply was promoted to an answer.