Suggest a route to prepare ethyl hydrogensulphate $\left({\mathrm{CH}}_{3}-{\mathrm{CH}}_{2}-{\mathrm{OSO}}_{2}-\mathrm{OH}\right)$ starting from ethanol $\left({\mathrm{C}}_{2}{\mathrm{H}}_{5}\mathrm{OH}\right)$.

For preparation of ethyl hydrogensulphate $\left({\mathrm{CH}}_{3}-{\mathrm{CH}}_{2}-{\mathrm{OSO}}_{2}-\mathrm{OH}\right)$ starting from ethanol $\left({\mathrm{C}}_{2}{\mathrm{H}}_{5}\mathrm{OH}\right)$, it is the two steps mechanism.
Step I Protonation of alcohol
${\mathrm{H}}_{2}{\mathrm{SO}}_{4}\to {\mathrm{H}}^{+}+{}_{-}\mathrm{OSO}_{2}\mathrm{OH}$
Step II Attack of nucleophile
Temperature should not be allowed to rise above 383 K, otherwise diethyl ether will be produced at 413 K or ethene at 433 K.