a
Reaction at equilibirium \({N_2}{O_4}\, \rightleftharpoons \,2N{O_2}\) According to Le chatelier's principle- \((a)\) addition of an inert gas at constant pressure will increase volume and equilibirium shifts towards more number of molecules. \((b)\) Decomposition of \(N_2O_4\) will be endothermic, so reaction wil move in forward reaction when temperature is increased.So, It is incorrect. It will not effect reaction (volume is constant) \((c)\) Increasing the pressure on a gas reaction shifts the position of equilibirium towards the side with fewer molecules. So, It will move in backward direction which leads to formation of \(N_2O_4\) from \(NO_2\)