**Given:** P_{1} = Initial pressure = 5 bar

V_{1} = Initial volume = 500 dm^{3} ; V_{2} = Final volume = 200 dm^{3}

**To find: **P_{2} = Final pressure

**Formula: **P_{1} V_{1} = P_{2} V_{2} (at constant n and T)

**Calculation: **According to Boyle’s law

P_{1} V_{1} = P_{2} V_{2 }(at constant n and T)

∴ P_{2 }= \(\frac{P_1V_1}{V_2}\) = \(\frac{5 \times 500}{200}\) = 12.5 bar

The minimum pressure required to compress 500 dm^{3} of air at 5 bar to 200 dm^{3} at 25 °C is 12.5 bar.