Answer
(a) 6.00 atm
(b) 2.40 atm
(c) 8.00 atm
(d) 0.750 atm
Work Step by Step
1. Conversion factor:
$1 \space L = 1000 \space mL$
2. According to the Boyle's Law:
$$P_1V_1 = P_2V_2 \longrightarrow \frac{P_1V_1}{V_2} = P_2$$
(a) $$P_2 = \frac{(1.20 \space atm)(5.00 \space L)}{1.00 \space L} = 6.00 \space atm$$
(b)
$V_2 = 2500. \space mL \times \frac{1 \space L}{1000 \space mL} = 2.500 \space L$
$$P_2 = \frac{(1.20 \space atm)(5.00 \space L)}{2.500 \space L} = 2.40 \space atm$$
(c)
$V_2 = 750. \space mL \times \frac{1 \space L}{1000 \space mL} = 0.750 \space L$
$$P_2 = \frac{(1.20 \space atm)(5.00 \space L)}{ 0.750 \space L} = 8.00 \space atm$$
(d)
$$P_2 = \frac{(1.20 \space atm)(5.00 \space L)}{8.00 \space L} = 0.750 \space atm$$
