See discussions, stats, and author profiles for this publication at: https://www.researchgate.

net/publication/312623113

Conductometric Studies Of Kinetics Of Ionic Reaction Between Ag+ And ClIn

Aqueous Solution

Article  in  International Journal of Scientific & Technology Research · January 2017

CITATIONS READS

0 306

5 authors, including:

Md. Miah Mohammad Rahman

Shahjalal University of Science and Technology University of Pittsburgh
27 PUBLICATIONS   193 CITATIONS    4 PUBLICATIONS   0 CITATIONS   

SEE PROFILE SEE PROFILE

Iqbal Ahmed Siddiquey

Shahjalal University of Science and Technology
50 PUBLICATIONS   521 CITATIONS   

SEE PROFILE

Some of the authors of this publication are also working on these related projects:

Synthesis of Ag or Fe doped TiO2-MWCNT Nanocomposite Thin Film and their Visible Light Induced catalysis in Dye Degradation and Antibacterial Activity View project

Fabrication of hydrazine sensor based on silica-coated Fe2O3 magnetic nanoparticles prepared by a rapid microwave irradiation method View project

All content following this page was uploaded by Iqbal Ahmed Siddiquey on 29 January 2017.

The user has requested enhancement of the downloaded file.

INTERNATIONAL JOURNAL OF SCIENTIFIC & TECHNOLOGY RESEARCH VOLUME 6, ISSUE 01, JANUARY 2017 ISSN 2277-8616

Conductometric Studies Of Kinetics Of Ionic

Reaction Between Ag+ And Cl- In Aqueous
Solution
Rezwan Miah, Debashis Sen, Azizur Rahman, Iqbal Ahmed Siddiquey, Mahbubul Alam

Abstract: In the present report, conductometric studies on the kinetic of formation of AgCl by ionic reaction between Ag+ and Cl  in aqueous solution
have been presented. The order of the mentioned reaction was determined by a new conductometric approach using half-life method. The obtained
result showed that the reaction follows a second-order kinetics. The second-order rate constant of the reaction was obtained conductometrically using
different initial concentrations of the reactants in the range of 2.5-5.0 mM. The average value of the rate constant was obtained as 20.648 L mol 1 s1 at
25 C.

Index Terms: Ionic reaction; Conductometric method; Order of reaction; Rate constant of reaction
————————————————————

1 INTRODUCTION The method involved the conversion of trace quantity of

+  extremely poor conducting boric acid present in the sample to
The reaction of sliver (Ag ) and chloride (Cl ) ions takes place
in aqueous solution and produces neutral AgCl. AgCl has a relatively better conducting complex boronmannitol using
many practical importance. For example, AgCl is used in mannitol. A gravimetric and complexometric titration method
preparing Ag/AgCl/Cl reference electrode which is extensively based on conductometric technique was described for the
used by the researchers in the field of electrochemistry. quantitative determination of brilliant green in water by R.
Ag/AgCl is a very stable and highly efficient photocatalytic Kakhki et al. [7]. The equilibrium constants and the
materials. Modification by cocatalyst and nanonization of thermodynamic parameters for the complex formation of b-
Ag/AgCl photocatalyst were done via a facile reduction– cyclodextrin with brilliant green (BG) and precipitation of silver
reoxidation route by using graphene oxide as the cocatalyst nitrate with BG were determined by conductance
modifier to enhance its performance by P. Wang et al. [1,2]. X. measurements in water by them. The complexation reactions
Yana et al. [3] described photocatalytic behavior of Ag@AgCl- of Mn2+, Co2+, Y3+ and ZrO2+ with the macrocyclic ligand, 4'-
RGO composite with both special electronic state structure of nitrobenz-15-crown-5 (4'-NB15C5), in acetonitrile (AN),
graphene and excellent visible light catalytic performance of methanol and AN–MeOH binary mixtures was studied at
Ag@AgCl. Phase composition of the photocatylst were various temperatures using the conductometric method by M.
characterized using X-ray diffraction. Scanning electron Esmaelpourfarkhani et al. [8]. The potentialities of
microscope and UV-visible absorption spectra were used to conductometric titration were investigated for the study of
characterize the surface morphology and spectroscopic protolytically active groups using organosilicas with
properties. Conductometric method for monitoring ionic immobilized acid groups of different types by V. N. Zaitsev et
reactions is very important and has received considerable al. [9]. It was shown by them that conductometry is a
scientific interest. For examples, the complexation reactions promising method for estimating the energetic heterogeneity of
between 3,5-diiodo-8-hydroxy quinoline and Zn2+, Ni2+ and the immobilized layer and the concentration of functional
Co2+ were studied in dimethylformamide (DMF)-ethanol binary groups on the surface of organosilicas. N-acetyl-cysteine
solvent systems at different temperatures using present in pharmaceuticals containing known quantities of the
conductometric method by A. Nezhadali et al. [4]. M. Rosés et drug was conductometrically titrated in aqueous solution with
al. [5] determined the limiting molar conductances and copper(II) sulphate using a conductometric cell coupled to an
dissociation constants of perchloric, hydrochloric, picric and autotitrator by B.C. Janegitz et al. [10]. Conductometric
benzoic acids as well as their tetrabutylammonium salts titration of fluoxetine hydrochloride in pharmaceutical products
conductometrically in propan-2-ol/water mixtures in wide using silver nitrate as titrant was described by E. R. Sartori et
composition range at 25 °C. S. Sharma et al. [6] studied the al. [11]. Formation of AgCl by the reaction of Ag+ and Cl is a
kinetics of base-catalyzed hydrolysis of ethyl acrylate in well-known ionic reaction but monitoring of kinetics of such an
ethanol-water (10–50% v/v) binary systems at the temperature ionic reaction is complex and time consuming. Kinetics of
range of 3045 °C using conductometric method. formation of precipitates of cerium oxalate and silver chloride
was studied by M.N. Parveen [12] using turbidity
measurements. Generally it is more convenient to study
kinetics of ionic reactions using conductometric technique as
often changes of other physical parameters, like turbidity, color
______________________ etc may not be achieved. The advantage of this method is that
it avoids the use of many chemicals and time consuming
 Rezwan Miah, Debashis Sen, Azizur Rahman, Iqbal tedious procedures. Conductometric technique could be a very
Ahmed Siddiquey, Mahbubul Alam convenient technique for studying AgCl formation and other
 School of Physical Sciences, Department of Chemistry, ionic reaction, as the conductance of the solution under
Shahjalal University of Science and Technology, Sylhet- investigation either increases or decreases with the progress
3114, Bangladesh of reaction. To the best of our knowledge, conductometric
 E-mail: mrmche@yahoo.com and rezwan-che@sust.edu technique has not been employed for investigating the kinetics
52
IJSTR©2017
www.ijstr.org
INTERNATIONAL JOURNAL OF SCIENTIFIC & TECHNOLOGY RESEARCH VOLUME 6, ISSUE 01, JANUARY 2017 ISSN 2277-8616

of the mentioned reaction between Ag+ and Cl forming AgCl. of the reacting solution is proportional to the remaining
In the present report, we present the measurements of concentrations of Ag+ and Cl. Therefore, x(0t) and
conductance of reaction mixture containing Ag+ and Cl in a(0t) and hence (ax)(t). Therefore, Eq. (3) can be
aqueous solution at 25 C. The data were then utilized in achieved by rearrangement of Eq. (2):
determining the order and rate constant of the reaction using a
new approach.

2 EXPERIMENTAL (3)

2.1 Procedure The value of second-order rate constant can thus be

The reaction of Ag+ and Cl was carried out in a glass vessel in calculated from the slope (1/ak) of a linear plot of t vs.
which the conductometer cell was immersed. The glass vessel ((ot)/t).
and the cell were thoroughly washed with water to remove any
abrasive materials, especially ionic species, which have very 3 RESULTS AND DISCUSSION
profound effect on the conductance. The reaction was carried
out at 25 C temperature. The reaction vessel with the cell was 3.1 Determination of time-dependence conductance
placed in a hot water bath that can control the temperature curves
within ± 1 C. Ag+ solution was taken in the reaction vessel Firstly, the conductance of the reacting mixture (R1) having
and that of Cl was taken in a test tube. Both the reaction [Ag+] = [Cl] = 2.5 mM was measured using conductometer.
vessel and the test tube were placed in the hot water bath until The obtained values of conductance were plotted against time
the desired temperature was achieved. After achieving the of the measurement and the result is shown in Fig. 1(A). The
temperature at 25 C, the Cl solution was poured into the curve shows that the value of conductance of the solution
reaction vessel in which the cell was previously placed. The decays exponentially with time, that is, it decays rapidly at
conductance of the reaction mixture was recorded within lower times but attains a level off trend at higher times. The
possible shortest time following the mixing of the reactants. decay of conductance is attributed to the consumption of the
The time of the reaction was measured by a digital stop-watch. uni-positive and negative Ag+ and Cl, respectively and the
AgNO3 and KCl solutions were prepared by dissolving aliquot formation of neutral AgCl. Similarly to the reaction mixture R1,
amounts of them in double-distilled water. The conductometer the conductance of R2 and R3 mixtures were also recorded,
was calibrated each time prior to measurements using 0.01 M plotted against time and the corresponding results are
KCl solution that has specific conductance equal to 1408 S presented in Fig. 1(B) and (C). Similar to reaction mixture R1,
cm1 at 25 C. Potassium chloride (KCl) (Merck, Germany) and the obtained curves also show the similar trend of decaying
silver nitrate (AgNO3), (Merck, Germany) were purchased and rapidly at lower experimental times and attaining a level off
used as received. KCl and AgNO3 solutions of same trend at higher times. The value of solubility product constant
concentrations of 5, 7 and 10 mM were prepared. 20 cm3 of of AgCl is 1.8  1010 at 25 C. The product of concentrations
each of AgNO3 and KCl solutions were mixed in the reaction of Ag+ and Cl used in the experiment exceeds the value of
vessel. Therefore, the final concentrations in the different solubility product constant. Therefore, the decrease in
reaction mixture were [Ag+] = [Cl] = 2.5 (R1), 3.5 (R2) and 5.0 conductance in the present experiment is obviously attributed
(R3) mM. to the precipitation reaction of Ag+ and Cl forming AgCl. Each
of the curves in Fig. 1 was extraplotted to y-axis and the initial
2.2 Methodology conductance (0) of each of the solutions was determined from
The relation between half-life and initial concentration of the intercept (t=0). The obtained values of 0 are summarized
reactant can be expressed by Eq. (1): in Table 1.

TABLE 1
Summarization of the values of 0 for the reaction mixtures
(1) R1, R2 and R3 at 25 C
Reaction
R1 R2 R3
where n is the order of the reaction, and are the half-lives mixture
of the reaction corresponding to the initial concentrations
equal to a1 and a2, respectively. Although Eq. (1) is derived for 0 / mS cm1 0.9496 1.2793 1.6585
half-life of reaction but it can be used for the completion of any
fraction of the reaction with two different initial concentrations.
The rate constant of a second-order reaction can be
expressed by the Eq. (2):

(2)

Where the symbols have their usual meanings. The terms

and 'a' can be expressed in conductance (). The conductance

53
IJSTR©2017
www.ijstr.org
INTERNATIONAL JOURNAL OF SCIENTIFIC & TECHNOLOGY RESEARCH VOLUME 6, ISSUE 01, JANUARY 2017 ISSN 2277-8616

attempted considering completion of any equal fraction of the

reaction. An equal decrease of conductance () is considered
as an indicator of completion of same fraction of the reaction
with different initial concentrations. For this purpose, the
values of were derived from the curves (A-C) in Fig. 1 at
different times and the values are summarized in Table 2.

TABLE 2
Summarization of the derived values of for reaction
mixtures R1, R2 and R3. The values were derived from the
curves in Fig. 1 (A-C)
2.5 mM (R1) 3.0 mM (R2) 5.0mM (R3)
/ mS / mS / mS
t/s t/s t/s
cm1 cm1 cm1
6.0 -0.0066 5.0 -0.0063 5.0 -0.0075
8.0 -0.0076 7.0 -0.0073 9.0 -0.0095
16.0 -0.0086 10.0 -0.0083 11.0 -0.0105
24.0 -0.0096 13.0 -0.0093 12.0 -0.0115
27.0 -0.0106 16.0 -0.0103 14.0 -0.0125
35.0 -0.0116 20.0 -0.0113 20.0 -0.0145
44.0 -0.0126 25.0 -0.0123 24.0 -0.0155
58.0 -0.0136 40.0 -0.0143 30.0 -0.0165
69.0 -0.0146 57.0 -0.0153 60.0 -0.0185
84.0 -0.0156 80.0 -0.0163 73.0 -0.0195

Fig. 2. Plots of  vs. t for different reaction mixtures:

(a) 2.5 (R1), (b) 3.0 (R2) and (c) 5.0 (R3) mM.

The obtained values of were plotted as a function of time

and the results are presented in Fig. 2. The times required
corresponding to  equal to 0.010, 0.115 and 0.125 mS
The data were derived from Fig. 1.
cm1 for reaction mixtures R1, R2 and R3 were derived from
Fig. 2 and summarized in Table 3.
Fig. 1. Curves of conductance (t) vs.
experimental time (t) for different reaction TABLE 3
mixtures: (A) [Ag+] = [Cl] = 2.5 (R1), (B) 3.5 Summarization of times required to decrease the conductance
(R2) and (C) 5.0 (R3) mM. The data were by different amount for different initial concentrations. The data
obtained at 25 C for the reaction of Ag+ and Cl were derived from Fig. 2
in aqueous solution.  / mS cm1 a / mM t/s n n (average)
2.5 8.5 2.5
+ 0.100 3.0 14.0 1.9 2.2
3.2 Determination of order of the reaction between Ag 5.0 19.5 2.2
and Cl 2.5 12.0 2.3
The Eq.(1) is generally used for half-life of reaction. But 0.115 2.2
3.0 19.0 2.1
versatility of this equation is that it can be applied to the time
5.0 28.8 2.2
required for completion of any specified fraction of the
2.5 15.5 2.6
reaction for two different initial concentrations.. In the present
0.125 3.0 27.0 2.1 2.3
article, the new approach to use Eq. (1) for the determination
of order of the ionic reaction between Ag+ and Cl is 5.0 41.0 2.4

54
IJSTR©2017
www.ijstr.org
INTERNATIONAL JOURNAL OF SCIENTIFIC & TECHNOLOGY RESEARCH VOLUME 6, ISSUE 01, JANUARY 2017 ISSN 2277-8616

The order of the reaction was calculated by putting the values

of 't' and 'a' in Eq. 1 for each pair of reaction mixture (R1, R2),
(R2, R3), (R1, R3). The average value of order was calculated
as 2.2, which can approximately be considered as 2. The
reaction between Ag+ and Cl forming AgCl in aqueous
solution was thus found to follow a second-order kinetics. The
obtained order is reasonable as being the reactants ionic, the
rate of the reaction is expected to depend on both of [Ag+] and
[Cl]. The present article therefore, describes a new
conductometric approach of determination of order which can
largely be employed to many ionic reactions.

3.3 Determination of rate constant of reaction between

Ag and Cl
+

The second-order rate constant of the reaction was calculated

using Eq. (2) modified for equal initial concentrations of Ag +
and Cl and replacing concentration with conductance (t). The
values of ((o-t)/t) were calculated at different times for the
reaction mixtures R1, R3 and R3 using (summarized in
Table 1) and (From Fig.1) The values of of the reaction
mixtures were plotted against the calculated values of
((ot)/t) and the results are shown in Fig. 3. The values
nicely fall on their respective straight lines. The regression
equations of the linear plots corresponding to reaction
mixtures R1, R2, R3 are presented by Eqs. (4)-(6),
respectively:

(4)

(5)

(6)

From the slopes( of the straight lines as presented by

the regression Eqs. (4)-(6), the rate constants were calculated
as 20.780, 20.836 and 20.329 L mol1 s1. The obtained values
are well consistent within an error of 0.3-2.4%.

4 CONCLUSIONS
The ionic reaction between Ag+ and Cl forming AgCl in
aqueous solution was studied using conductometric method.
The conductances of the reaction mixture corresponding to
zero time were obtained as 0.9496, 1.2793 and 1.6585 mS
cm1 from the intercept of the t vs. t plots for different reaction
mixtures. The times required for the decrease of conductance
() to the same extent for all the reaction mixtures were Fig. 3. Linear plots of vs. for different
obtained at several values of . The order of the reaction was reaction mixtures: (A) 2.5 (R1), (B) 3.5 (R2) and (C)
then calculated as ca. 2.0 using the obtained time. A new 5.0 (R3) mM. The data were derived from Fig. 1.
conductometric approach for determination of order of ionic
reaction was achieved. A modified second-order rate ACKNOWLEDGEMENTS
expression was developed in terms of conductance and the The present work was financially supported by the research
rate constants of the reaction were calculated as 20.780, grants (code PS-06) granted to Prof. Dr. Md. Rezwan Miah
20.836 and 20.329 L mol1 s1 from the values of slopes of the from the Research Center, Shahjalal University of Science
vs. ((o-t)/t) linear plots for different concentrations. The and Technology, Sylhet-3114, Bangladesh and the project
values were well-consistent within the experimental errors. granted to Prof. Dr. Mohammad Abul Hasnat from the Ministry
The present article demonstrate a very important new of Education, People's Republic of Bangladesh.
approach of determination of order that can widely be
employed for other ionic reactions.

55
IJSTR©2017
www.ijstr.org
INTERNATIONAL JOURNAL OF SCIENTIFIC & TECHNOLOGY RESEARCH VOLUME 6, ISSUE 01, JANUARY 2017 ISSN 2277-8616

References [12] M..N. Parveen, ‖Kinetic Measurements of Precipitation

[1] J. Tian, R. Liu, G. Wang, Y. Xu, X. Wang, H. Yu, Reaction of Inorganic Compounds,‖ Int. J. Recent Trends
―Dependence of Metallic Ag on the Photocatalytic Activity in Sci. Techn., ISSN 2277-2812 E-ISSN 2249-8109,
and Photoinduced Stability of Ag/AgCl Photocatalyst,‖ J. Special Issue, ACTRA-INDIA, pp. 12-14, Sept. 2013.
Applied Surf. Sci.., vol 319, pp. 324-331 , Nov. 2014.

[2] P. Wang, T. Ming, G. Wang, X. Wang, H. Yu, J. Yu,

‖Cocatalyst Modification and Nanonization of Ag/AgCl
Photocatalyst with Enhanced Photocatalytic
Performance,‖ J. Molecular Catal. A: Chemical, vol 381 ,
pp. 114-119 , Jan. 2014..

[3] X. Yana, S. Pengb, H. Zhua, ‖Photocatalytic Properties of

Ag@AgCl-RGO Composites,‖ IERI, Procedia, vol 5, pp.
223-231, 2013.

[4] A. Nezhadali, Gh. Taslimi,―Thermodynamic Study of

Complex Formation between 3,5-Di iodo-hydroxy
quinoline and Zn2+, Ni2+ and Co2+ Cations in some Binary
Solvents Using a Conductometric Method,― J. Alexandria
Eng. vol 52, pp. 797, 2013.

[5] M. Rosés, M.J. Bonet, E. Bosch, ‖Conductometric

Determination of Dissociation Constants of Several Acids
and Their Tetrabutylammonium Salts in Propan-2-
ol/Water Mixtures,― Anal. Chimi. Acta, vol 333, pp. 241,
1996.

[6] S. Sharma, J. Ramani, J. Bhalodia, ‖Kinetic Study of

Specific Base Catalyzed Hydrolysis of Ethyl Acrylate in
Water-Ethanol Binary System,― Russian J. Phys. Chem.,
vol 87, pp. 730, 2013.

[7] R. Kakhki, S. Heydari, ‖A Simple Conductometric Method

for Trace Level Determination of Brilliant Green in Water
Based on β-Cyclodextrin and Silver Nitrate and
Determination of Their Thermodynamic Parameters,‖
Arabian J. Chem., vol 7, pp. 1086, 2014..

[8] M. Esmaelpourfarkhani, G.H. Rounaghi and M.H. Arbab

Zavvar, ‖Conductometric Study of Complexation Reaction
of 4′-Nitrobenzo-15-Crown-5 with Mn+2, Co+2, Y+3, and
ZrO+2 Cations in Acetonitrile, Methanol and their Binary
Solvent Solutions,‖ Russian J. General Chem., vol 84,
pp. 1219, 2014..

[9] V. N. Zaitsev, N. G. Kobylinskaya, L. S. Kostenko and V. I.

Gerda, ‖Conductometric Determination of the
Concentration of Acid Centers on Functionalized
Materials,‖ J. Anal. Chem., vol 63, pp. 779, 2008.

[10] B.C. Janegitz, W.T. Suarez, O. Fatibello-Filho and L.H.

Marcolino Junior, ‖Conductometric Determination of N-
acetylcysteine in Pharmaceutical Formulations Using
Copper(II) Sulphate as Titrant,‖ Anal. Lett., vol 41, pp.
3264, 2008.

[11] E.R. Sartori, W.T. Suarez and O. Fatibello-Filho,

‖Conductometric Determination of Fluoxetine
Hydrochloride in Pharmaceutical Formulations,‖ Anal.
Lett., vol 42, pp. 659, 2009.

56
IJSTR©2017
View publication stats
www.ijstr.org