Mass and molar balances

Packed towers are used in industrial gas$-$liquid absorption$.$ In the schematic below, a counter$-$current operation of an absorption column is shown. Please use the mole fraction $x_1$ for the component $i$ in the liquid phase and the mole fraction $y_i$ for the component $i$ in the gas phase, respectively.

Set up a general molar balance using the counter$-$current operation of the absorption column $($in the schematic below $y=y_i$ and $x=x_i$ while the indices $"0"$ and $"$L define the bottom and the top of the column, respectively.

Set up a general mass balance using counter$-$current operation of the absorption column.

Assume $y_0=0\mathrm{.}2mo\frac{l}{m}ol,$ and $y_L=0\mathrm{.}01mo\frac{l}{m}ol$ and $x_L=0\mathrm{.}005mo\frac{l}{m}ol,$ what is the value for $x_0?$

Assume $y_0=0\mathrm{.}2mo\frac{l}{m}ol,$ and ${}_L=0\mathrm{.}01mo\frac{l}{m}ol$ and $x_L=0mo\frac{l}{m}ol,$ what is the value for $x_0?$ Please define all the symbols used.