There are TWO reactions possible depending on the sequence:
If you add ethanol dropwise to sulfuric acid an elimination reaction will take place:
C2H5OH + H(+) → C2H4 + H2O + H(+)
If you add sulfuric acid dropwise to pure ethanol you will get diethyl ether. That’s a substitution reaction:
2 C2H5OH + H(+) → H3C-CH2-O-CH2-CH3 + H2O + H(+)
Hope that helps :)