Monoatomic, diatomic and triatomic gases whose initial volume and pressure are same, are compressed till their volume become half the initial volume. (1) If the compression is adiabatic then monoatomic gas will have maximum final pressure. (2) If the compression is adiabatic then triatomic gas will have maximum final pressure. (3) If the compression is adiabatic then their final pressure will be same. (4) If the compression is isothermal then their final pressure will be different.