Assume ideal gas behaviour for all the gases considered and neglect vibrational degrees of freedom. Separate equimolar sample. Separate equimolar samples of Ne, `O_(2)` , `CO_(2)` and `SO_(2)` were subjected to a two process as mentioned. Initially all are at same state of temperature and pressue.
Step I `rarr` All undergo reversible adiabatic expansion to attain same final volume, which is double the original volume thereby causing the decreases in their temperature.
Step `rarr` After step I all are given appropriate amount of heat isochorically to restore the original temperature.
Mark the correct option(s) :

Options

A. Due to step I only, the decrease in temperature will be maximum for Ne
B. During step II, heat given will be minimum for `SO_(2)`
C. There will be no change in internal energy for any of the gas after both the steps of process are competed
D. The P-V graph of `O_(2)` and `CO_(2)` will be same

Answer

A, C, D

Explanation

First step is adiabatic (q = 0) so `DeltaU_(1)=w_(1)`
Second step is isochoric (w = 0)

So, `" "DeltaU_(2)=q_(2)`
`because` initial and final temp. are same
`therefore" "DeltaU_("toal")=DeltaU_(1)+DeltaU_(2)=0`
` "or "w_(1)+q_(2)=0`
Max. work done by the gas, `SO_(2)` is (area) under the curve
so, `SO_(2)` absorbed
`because " "gamma_(SO_(2))lt gamma_(CO_(2))=gamma_(O_(2))=ltgamma_(Ne)`
so, max. decrease in temp. of Ne due to step 1.