CaCO3→1073k∆CaO+CO2Reverse reaction takes place in a closed vessel . To prevent backward reaction

CaCO3s⇌1037 K CaOs+CO2gTo prevent the back ward reaction the CO2 has to remove from the reaction mixtureAccording to lechatlier principle the equilibrium shits in the direction to increases the number of molesWhen you remove the CO2 from the reaction mixture, then on the products side number of  gaseous moles decreases, therefore the  equilibrium shifts in forward direction to increase number of moles on product side