Fugacity: It is derived from Latin, expressed as fleetness or escaping ...
Fugacity: It is derived from Latin, expressed as fleetness or escaping ...
Fugacity: It is derived from Latin, expressed as fleetness or escaping ...
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x<br />
i<br />
dG<br />
dx<br />
1<br />
i<br />
0 -----(3)<br />
Gi RT ln f i <br />
at constant temperature<br />
dGi RT ln f i<br />
----(4)<br />
dx1<br />
dx1<br />
substituting equation (4) in equation (3)<br />
RT ln f<br />
xi<br />
dx<br />
d ln f<br />
xi<br />
dx<br />
1<br />
1<br />
i<br />
i<br />
0<br />
0------(5)<br />
F<strong>or</strong> binary system<br />
d ln f1<br />
d ln f 2<br />
x1 x2<br />
0 ----(6)<br />
dx dx<br />
1<br />
x d f x d ln f 0 -----(7)<br />
1<br />
ln 1 2 2<br />
1<br />
Equation (5) (6) and (7) are Gibbs Duhem equation in terms of fugacites and thus<br />
applicable f<strong>or</strong> both liquid and vap<strong>or</strong> ph<strong>as</strong>e<br />
F<strong>or</strong> liquids<br />
f x f<br />
i<br />
i<br />
i<br />
i<br />
i<br />
ln f ln<br />
ln x ln f<br />
i<br />
differentiating with respect to x1<br />
1<br />
1<br />
i<br />
d ln f i d ln<br />
i d ln xi<br />
d ln f i<br />
-------(8)<br />
dx dx dx dx<br />
1<br />
i<br />
fi <strong>is</strong> a pure component ffugacity it does not vary with x1<br />
Substituting equation (8) in equation (5)<br />
d ln<br />
i d ln x<br />
xi<br />
xi<br />
dx dx<br />
1<br />
1<br />
i<br />
=0<br />
0<br />
1<br />
=0
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