Ethanol is heated with conc. $\mathrm{H}{}_2\mathrm{SO}{}_4$ at 413 K with the alcohol in excess. The main product is

At 413 K with excess alcohol, ethanol is dehydrated bimolecularly: ethyl hydrogen sulphate is attacked by a second molecule of ethanol in an ${\mathrm{S}}_{\mathrm{N}}2$ step to give $\mathrm{C}{}_2\mathrm{H}{}_5-\mathrm{O}-\mathrm{C}{}_2\mathrm{H}{}_5$. Ethene is formed only at about 443 K or above (intramolecular dehydration), so ethoxyethane is the answer.