$1.$ Choose a reversible reaction IN GAS PHASE where the change in the number of moles is different from zero.

$2.$ Write the equation to calculate the equilibrium conversion.

$3.$ Obtain the equation to calculate the time of the reversible reaction from point $1$ that is carried out in a Batch reactor of VARIABLE volume to reach $90\%$ of the conversion to equilibrium at isobaric and isothermal conditions.

$4.$Assign values $$to the stoichiometric coefficients, the initial charges, the constants, the pressure and temperature.

$5.$ Calculate the equilibrium conversion.

$6.$ Calculate the time it takes for the reversible reaction carried out in the VARIABLE volume Batch reactor at isobaric and isothermal conditions to reach $90\%$ conversion to equilibrium. thank u so much :)