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Grade 12th passPhysical Chemistry

why does addition of inert gas in an equilibria has no effect at constant volume.
why does it have a effect on the equilibrium if its put in at a constant presssure?

Profile image of AISHWARYA SHARMA
10 Years agoGrade 12th pass
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1 Answer

Profile image of Jayant Kishore
10 Years ago
Since , Q= ((ncC . nDD)/(nAA . nBB)) . (PT/nT)∂n     for an eqbm A+B → C+D  where PAND nT are total pressure and moles at eqbm. and ∂n=(nc+nD)-(nA+nB)  where A,B,C,D are gases.
In case of case of addition of inert gas : 
At constant volume  PT/nT will remain constant because PT and nT  increase in the same ratio.
so, Q will not change , so eqbm will be unaffected.
At constant pressure , equbm shifts in the direction where there are higher no. of gaseous species{ie in forward direction if ∂n>0 and vice versa} . This is because (PT/nT) T will increase.