Chemistry-Lab

0.000

Determination of equivalent conductance of NaCl at different concentrations

Concentration of
NaCl solution (N)		 √C(M0.5) Conductance,
L(mmho)		 Equivalent conductance, Λ (mmho cm2
equivalent-1) = (1000 L X)/C
0.05 0.223607 5.95 138040
0.025 0.158114 2.77 128528
0.0125 0.111803 1.47 136416
0.0062 0.0787401 0.77 144065
0.0031 0.0556776 0.41 153419
0.0016 0.04 0.23 166750

Determination of equivalent conductance of HCL at different concentrations

Concentration of
HCL solution (N)		 √C(M0.5) Conductance,
L(mmho)		 Equivalent conductance, Λ (mmho cm2
equivalent-1) = (1000 L X)/C
0.05 0.223607 13.7 317840
0.025 0.158114 7.65 354960
0.0125 0.111803 4.15 385120
0.0062 0.0787401 2.14 400387
0.0031 0.0556776 1.12 419097
0.0016 0.04 0.6 435000

Determination of equivalent conductance of CH3COONa at different concentrations

Concentration of
CH3COONa solution (N)		 √C(M0.5) Conductance,
L(mmho)		 Equivalent conductance, Λ (mmho cm2
equivalent-1) = (1000 L X)/C
0.05 0.223607 2.26 52432
0.025 0.158114 1.46 67744
0.0125 0.111803 0.92 85376
0.0062 0.0787401 0.54 101032
0.0031 0.0556776 0.31 116000
0.0016 0.04 0.17 123250

Figure 1: Plot of equivalent conductance vs √C for NaCl, HCl and CH3COONa

The Y-axis intercept for NaCl, HCl and CH3COONa are 169960 mmho cm2 eqv-1, 454680
mmho cm2 eqv-1, 135130 mmho cm2 eqv-1, respectively.
The equivalent conductance of acetic acid at infinite dilution (Λ0) is given as,
Λ0 = Λ0CH3COONa + Λ0HCl - Λ0NaCl
= (135130+454680-169960) mmho cm2 eqv-1
= 419850 mmho cm2 eqv-1

Determination of exact concentration of acetic acid solutions

Approximate concentration of
acetic acid solutions, C (N)		 Volume of standard NaOH
required for titration (mL)		 Actual concentration of
acetic acid solutions, C (N)
1 9.1 0.91
0.5 4.8 0.48
0.25 2.4 0.24

Determination of dissociation constant of acetic acid by conductance measurement

Exact
concentration
of acetic acid
solutions,
C (N)		 Conductance
,L (mmho)		 Equivalent
Conductance,
Λ (mmho
cm2 eqv-1) =
(1000LX)/C		 Equivalent
conductance
at infinite
dilution of
acetic acid,
Λ0(mmho
cm2 eqv-1)
Degree of
dissociation
α = Λ/Λ0		 Dissociation
constant of
acetic acid,
Ka=
(cα2)/(1-α)
0.91 1.71 1873.85 419850 0.00446313 2.46569e-05
0.48 1.14 2755 0.00656187 2.08044e-05
0.24 0.79 3818.33 0.00909452 2.00326e-05
0.12 0.49 4736.67 0.0112818 1.54478e-05
0.06 0.32 6186.67 0.0147354 1.32228e-05

Instructions

lets start the experiment

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