If $K_{a_1}$ and $K_{a_2}$ of ${\mathrm{H}}_2{\mathrm{SO}}_4$ are ${10}^{-2}$ and ${10}^{-6}$ respectively then :

$K_{a_1}>K_{a_2}$ because it is easy to abstract ${\mathrm{H}}^{+}$ from ${\mathrm{H}}_2{\mathrm{SO}}_4$ and less easy to abstract ${\mathrm{H}}^{+}$ from ${\mathrm{HSO}}_4^{-}$

$K_{a_1}$ and $K_{a_2}$ are measured in ${\mathrm{H}}_2\mathrm{O}$

the ${\mathrm{H}}^{+}$ ion cone. of 0.01 M ${\mathrm{H}}_2{\mathrm{SO}}_4$ will be less than 0.02 M.

$K_{a_1}$ and $K_{a_2}$ may be measured in acetic acid