sir if areaction of gas takes place in a tube gases occupy the volume of tube so each gases’’’volume=volume of container but howincase of nmerical some volume is changed products’’vol NOt=reactant

Dear student the volume of gases remain same even after reaction and product formation, but partial pressure of indivdual gases might change due to chane happening in their number of moles .;
So volume of product gas=volume of reactant gas =volume of container …..at all the time