0.5 mole each of two ideal gases`A (C_(v,m)=(5)/(2)R)` and `B (C_(v,m)=3R)` are taken in a container and expanded reversibly and adiabatically, during this process temperature of gaseous mixture decreased from 350 K to 250 K. Find `DeltaH` (in cal/mol) for the process :

Options

A. `-100 R`
B. `-137.5 R`
C. `-375 R`
D. None of these

Answer

C

Explanation

`DeltaH=(n_(1)C_(p,m_(1))+n_(2)C_(p,m_(2)))DeltaT`
`=(0.5 xx(7)/(2)R+0.5xx4R)(-100)`
`=-375 R`