Answer
a. The volume decreases.
b. The volume does not change.
c. The volume increases.
Work Step by Step
a. Volume is inversely proportional to the Pressure. Thus, when the pressure increases at constant temperature and amount of gas, the volume decreases.
b. If the pressure, the temperature and the amount of gas are constant, the volume will not change.
According to the Boyle's Law:
$$P_1V_1 = P_2V_2$$ $$(2.0 \space atm)V_1 = (2.0 \space atm)V_2$$ $$V_1 = V_2$$
c. When the pressure decreases at constant temperature and amount of gas, the volume increases.
