Sarath Project Final

8/2/2019 Sarath Project Final

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CHL705: ELECTROKINETIC TRANSPORT PHENOMENA

PRACTICAL SESSION SOLUTIONS

1. Let us consider the reaction

For the above equilibrium reaction the association constant is given by

similarly dissociation constant is given by We know that applying logarithm to above equation we get

but Hence -

3.

The concentration of is 0.01 mol/dm3 the dissociation of BaSO4 is given by

Let the solubility of BaSO4is x

[ = 0.01+ xKsp = 1.210

10mol

2/dm

6

By definition 1.210

10 = (x)(0.01+x)

Solving the above equation we get x =1.2 x 10-8 mol/dm3


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4) The dissociation of CaSO4 is given by

(1)Similarly the dissociation of SrSO4 is given by

(2)By dividing (1)/(2) we get

=

Here both are unknowns hence we use the axiom that sum of all charges = 0

(electroneutrality)

From equation (2)

Upon solving we get

5)

The positive charge comes from H3O

+ and negative ion A- and OH- hence

b) for sparingly soluble salt

Ksp = 3


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6. a) The dissociation of calcite is given by

We know that GO = -RT lnKGO =- 8.314 x 298 x ln(8.9 x 10-9) = 45927.28 J/molthe dissociation of aragonite is given by

GO = - 8.314 x 298 x ln(1.22 x 10-8) = 45145.89 J/mol

b) given

= 10-4 Ksp =

upon substituting the values we get

therefore it is impossible to dissolve in the solution.Similarly for aragonite therefore it is dissolve in the solution.

But we know first three terms indicate GO

G

O

For calcite

288.717 J/molFor aragonite

7. dissociation of KCl is given by

Ionic strength is given by


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9/20b)

IIAz

i

i

1log

2

To calculate activity co-eficient of K+ is given below here A =0.510 mol-1/2dm3/2 and ionicstrength is I=0.1

1.01

1.05.0log

i

There fore = 0.758

For Mg2+

1.01

1.045.0log

xi

0.331

For La3+

=

1.01

1.095.0log

xi

0.0831

c) replace the concentration with c=0.5 mol/dm3 and calculate the activity co-efficient


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8. given that

= = GO

We know Hence the above equation can be written as

=

G

O+

Let the concentration of GO + = GO + = GO +

b)

= GO + Let the concentration of

GO + )) = Therefore

=

10) =


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Taking log on both sides of the above equation

[[] But activity co-efficient is expressed in terms of ionic strength and it is given by

IIAz

i

i

1log

2

Let us assume A=0.510 mol-1/2

dm3/2

II

cuso

1

2log 4

Substituting the above equation in the log equation

II 12

11) we know that

IC can be calculated as

Substitute the values of concentration and obtain the values of K.

12) Bjerrium distance is given by


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q = = 2.8 nmby taking the sum of radii for a we obtain KA = 5222 M

-1for

we obtain = 0.648 similarly do for other values.

.


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