From ideal gas equation, pV=nRT ⇒V=pnRT
For n=1mole V=pRT ⇒V∝T ∴ The molar volume of CO2 at
a)NTP V=10.0821×273=22.4L
b) 0∘C and 2.0atm V=2.00.0821×273=11.2L
c) 127∘C and 1atm V=10.0821×400=32.84L
d) 273∘C and 2atm V=20.0821×546=22.4L
Therefore the molar volume of CO2 is maximum at 127∘C and 1atm.