The graph below shows how the pressure and volume of a gas vary when the
number of moles and the temperature of the gas are held constant. what
happens to the pressure inside a sealed syringe of gas as the volume of the
syringe increases?
(sorry the picture sucks)

The pressure of the gas decrease as the volume increases.

Option A.

The Boyle's law states that in a situation of constant volume and constant temperature, as the pressure of an ideal gas increase, the volume decreases and vice versa. So the mass and the temperature remaining constant, the pressure and the volume of an ideal gas are inversely proportional.

So P ∝ 1/V.

Thus, inside a sealed tube, the mass of the gas is constant. The temperature of the region is said to be constant under the short span of time of this experiment. So as the syringe is pulled, the volume do increase, so the pressure inside the vial decrease.

This is what is plotted in the graph which gives a rectangular hyperbola.

the correct answer is:

a. formation of precipitation