In the reaction 2ClF3=Cl2+3F2, if there is increase in volume of container, pressure exerted would be low so why shift from RHS does not take place as number of moles on RHS is more ?? and then how dissociation of 2ClF3 is favoured??

dear friend you have missed one thing this is an exmaple of endothermic reaction so on increasibg the volume of the container the temperature will decrease hence the reaction will favour formation of ClF3 and dissociation will not be favoured
delta H for this reaction is 329Kj