hi all
i am a beginner,and not able to recognize the type of harp I hv. it has 24 holes and chromatic written on it,
But assuming it is chromatic when i play the notes given in this site it does not produce the same tune.plese help

24 holes, now are they a line of twelve, on top of a line of twelve that is twentyfour holes,and not having a side valve, this will probably be a Tremelo Harmonica

If it has 24 holes in a line with a valve it will be a chromatic Harmonica of a sort that I have not seen, for usually valve Chromatics come as 10, 12, or 16 holes.
You can find some songs tabbed for tremelo and there are some on this site posted by member Yukon, try them with your Harmonica

As you say, anything tabbed for Diatonic will not sound right on yours if it is a Tremelo Harmonica. I have a Chinese made Tremelo that has two rows of 20 holes one row on top of the other, and there is nothing on the chrome covers to tell its make or key, even the box it came in has nothing on it.