When the volume of a container with a reaction at equilibrium is reduced, the system will respond according to Le Chatelier's Principle, which states that when a change is applied to a system at equilibrium, the system will adjust itself to counteract the change and re-establish equilibrium.In this case, reducing the volume of the container from 1 liter to 0.5 liters will increase the concentration of the reactants and products. The system will respond by shifting the equilibrium position to counteract this change.If the reaction is exothermic releases heat , the equilibrium will shift towards the side with fewer moles of gas to counteract the increase in concentration. This is because the reaction will consume more reactants to produce fewer moles of gas, thus decreasing the pressure and re-establishing equilibrium.If the reaction is endothermic absorbs heat , the equilibrium will shift towards the side with more moles of gas to counteract the increase in concentration. This is because the reaction will consume more reactants to produce more moles of gas, thus increasing the pressure and re-establishing equilibrium.In summary, the effect on the equilibrium position of the reaction depends on whether the reaction is exothermic or endothermic and the number of moles of gas on each side of the reaction. The system will adjust itself according to Le Chatelier's Principle to counteract the change in volume and re-establish equilibrium.