Consider the following reaction at equilibrium : NO_2 (g)+CO (g)↔NO(g)+CO_2 (g) . suppose the volume of the system is decreased at a constant temperature, what change will this cause in the system?
No shift will occur

I need the full reason

If the volume of the system is decreased, no shift will occur

In the equilibrium system, according to Le Chatelier, if there is a reaction there will be action  

Reaction = - action  

The reaction taken by the system is to shift the reaction to the right or left.  

The composition of chemical reactions in equilibrium can be influenced by temperature, pressure, and concentration.  

While on the change in pressure(volume), then the addition of pressure, the reaction will shift towards a smaller reaction coefficient  ((the fewest moles of gas  )

This pressure usually affects the gas equilibrium system(only count the number of moles of gases)

Reaction

NO₂ (g)+CO (g)↔NO(g)+CO₂(g)

The reactant side of the equation has 2 moles of a gas(1 mole NO₂ and 1 mole CO) ; the product side has 2 moles (1 mole NO and 1 mole CO₂)

So the total number of moles from both sides is the same(2 moles) so that the change in volume (pressure) does not change the direction of equilibrium⇒No shift will occur