h25o4 ???? No such substance. I think you mean H2SO4 ; Note '5' for 's'
H2SO4 is Sulphuric Acid.
NB When writing chmeical formulae , single letter elements are ALWAYS written as a CAPITAL letter. Double letter symbols are always written , first letter is a CAPITAL letter aand the second letter is small/lower case. This is the agreed international standard. !!!!!
So h25o4 should be written as H2SO4