Scholars research library

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Scholars research library

Archives of Applied Science Research, 2011, 3 (5):70-84 (http://scholarsresearchlibrary.com/archive.html)

ISSN 0975-508X CODEN (USA) AASRC9

Molar volume and ultrasonic studies of some alkaline earth metal chlorides in water + NaCl + fructose system

Shashi Kant, Dharmvir Singh, Sunil Kumar

Department of Chemistry, Himachal Pradesh University, Summer Hill, Shimla, India ______________________________________________________________________________

ABSTRACT

The density and ultrasonic velocity measurements were made for magnesium chloride (MgCl

2

), calcium chloride (CaCl

2

) and strontium chloride (SrCl

2

) in 2% fructose prepared in 0.01m aqueous NaCl at temperatures 303.15, 308.15, 313.15 and 318.15K. The measured parameters were then used to calculate various thermodynamic and acoustic parameters such as apparent molar volume (

), limiting apparent molar volume (

), limiting apparent molar volume expansibility (

), adiabatic compressibility ( ), intermolecular free length (

), relaxation time and Gibb’s free energy of activation for relaxation process

. The results have been discussed in terms of ion-solvent, ion-ion interactions. Further structure making/breaking behaviour of MgCl

2

, CaCl

2

and SrCl

2

has been discussed and structure breaking behaviour of these metal chlorides in 2% fructose in 0.01m aqueous NaCl has been reported.

Keywords: Molar volume, adiabatic compressibility, alkaline chloride, fructose.

______________________________________________________________________________

INTRODUCTION

Ion-ion and ion-solvent interactions can furnish useful information on structural changes occurring in the solutions. Apparent molar volume and acoustic parameters may be used to investigate these interactions in the solutions. Multi-component solutions similar to bio-fluids are used extensively these days for better understanding of biological processes [1-8]. We have studied MgCl

₂

, CaCl

₂

and strontium chloride (SrCl

₂

) in 2% fructose in 0.01m aqueous NaCl.

Fructose, sodium chloride, magnesium chloride, calcium chloride and strontium chloride are active constituents of bio-fluids. The study was carried out at four different temperatures 303.15, 308.15, 313.15 and 318.15 K to understand the nature of ion-solvent and ion-ion interactions by measuring density, molar volume, sound velocity etc. of their solutions.

MATERIALS AND METHODS

Triply distilled water with specific conductance in the range of 0.1×10

⁻⁶

to 1.0×10

⁻⁶

Ω

⁻¹

cm

⁻¹

was

used for preparation of the solutions. Magnesium chloride, calcium chloride, strontium chloride

(2)

and fructose (Anala R) were dried under vacuum for 24 h before use. All the solutions were prepared by weight and conversions of molality to molarity were done by using the standard expression [9]. The concentration range of MgCl

₂

, CaCl

₂

and SrCl

₂

was 0.01 m to 0.12 m. Firstly 0.01 m NaCl was prepared then this solution is used as solvent to prepare 2% fructose solution.

Finally this 2% fructose solution is used as main solvent to prepare 0.01 m to 0.12 m MgCl

2

, CaCl

₂

and SrCl

₂

solutions. The density and velocity of sound were measured with the help of DSA (Density and Sound Analyser) 5000, Antor Paar, GmbH, Garz, Austria. All measurements were made at 303.15, 308.15, 313.15 and 318.15 K with an accuracy of ±0.05 K. Accuracy in density and ultrasonic velocity measurements are ±1.4×10

⁻⁵

g cm

⁻³

and ±1.3×10

⁻¹

m s

⁻¹

respectively.

RESULTS AND DISCUSSION

a. Molar volume studies

The apparent molar volume (

_v

) of MgCl

₂

, CaCl

₂

and SrCl

₂

in 2% fructose in 0.01m aqueous NaCl solution have been obtained by using Eq. (1) and are reported in table-1 along with corresponding density values.

v

= (M

₂

/ρ) − 1000(ρ − ρ

⁰

)/mρρ

⁰

(1)

where ρ

⁰

is the density of solvent, ρ is the density of solution, m the molality of solution and M

2

the molecular weight of electrolyte. Errors in

_v

were calculated from equation (2) [10]

∆

v

= (2∆ρ/ρ

²

)(1000/m+M

₂

) (2)

Equation (2) assumes error to be associated with the density of solution (ρ) and solvent (ρ

⁰

).

Moreover, errors associated with determination of solution concentration are not the limiting factor while calculating the apparent molar volumes. The errors as derived from equation (2) were estimated to range from ±0.01 cm

⁻³

mol

^-1

at 0.01 m concentration to ±0.08 cm

⁻³

mol

^-1

at 0.12 m concentration.

The densities of various solutions of magnesium chloride, calcium chloride and strontium chloride in 2% fructose in 0.01m aqueous NaCl vary linearly with C _, obey Root's equation and justify the use of Masson's Eq. (3) for the estimation of the limiting apparent molar volume

C S

_v

o v v

= φ +

φ ⁽³⁾

Where φ

_v^o

^{and S}

v

are calculated from the intercept and slope from the extrapolation of the plots

of φ

_v

versus C . The values of limiting apparent molar volume ( φ

_v^o

) and slopes (S

_v

) along with

standard errors are reported in Table 2. The slope S

v

in Masson's equation may be attributed to

be as a measure of ion–ion or solute–solute interactions [11–13]. Low and positive values of S

_v

for MgCl

2

, CaCl

2

and SrCl

2

account for weak ion–ion interactions. There is a decrease in inter

ionic interactions with increase in temperature for Magnesium chloride, calcium chloride and

barium chloride in in 2% fructose in 0.01m aqueous NaCl solutions which may be due to more

solvation of electrolytic ions with rise in temperature.

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The φ

^o_v

is a measure of ion–solvent interactions [14]. The positive values of φ

^o_v

for MgCl

2

, CaCl

2

and SrCl

2

shows positive ion–solvent interactions. The φ

^o_v

values for MgCl

2

, CaCl

2

and SrCl

2

increase with increase in temperature and it may be due to more solvation of electrolytic ions as a result of decrease in hydrogen bonding between solvent molecules with rise in temperature, thus making more free solvent molecules available for solvation of electrolytic ions.

The temperature dependence of φ

^o_v

for MgCl

2

, CaCl

2

and SrCl

2

can be expressed as:

0

φ

v

= -2841.61 + 18.19T- 0.028T

²

(4) (For MgCl

2

in 2% fructose in 0.01m aqueous NaCl system)

0

φ

v

= -4731.26+29.43T- 0.045T

²

(5) (For CaCl

₂

in 2% fructose in 0.01m aqueous NaCl system)

0

φ

v

= -4195.29 + 27.025T - 0.042T

²

(6) (For SrCl

2

in 2% fructose in 0.01m aqueous NaCl system) where ‘T’ is the temperature in Kelvin.

The limiting apparent molar volume expansibility, φ

^o_E

= ( ∂ φ

^ov

/ ∂ ^T)

p

calculated for MgCl

₂

, CaCl

₂

and SrCl

2

from Eqs. (4)–(6) is given in Table 2. The values of φ

^o_E

decrease with the increase in temperature for MgCl

₂

, CaCl

₂

and SrCl

₂

which indicates the absence of “caging effect” and their behaviour is just like common electrolytes [15–17]. The structure making/breaking capacity of MgCl

2

, CaCl

2

and SrCl

2

may be interpreted with the help of Hepler's reasoning, i.e. on the basis of sign of ( ∂

²

φ

^ov

/ ∂ ^T

²

⁾

p

[18]. It has been shown from general thermodynamic Eq. (7)

⁄

7 where is the partial molar heat capacity at infinite dilution. From Eq. (7), it is clear that

structure making electrolytes should have a positive value of ( ∂

²

φ

^ov

/ ∂ ^T

²

⁾

p

and structure breaking electrolytes should have negative value of ( ∂

²

φ

^ov

/ ∂ ^T

²

⁾

p

. For MgCl

₂

, CaCl

₂

and SrCl

₂

the sign of ( ∂

²

φ

^ov

/ ∂ ^T

²

⁾

p

has been found to be negative which suggests that MgCl

₂

, CaCl

₂

and SrCl

₂

act as structure-breaker in 2% fructose in 0.01m aqueous NaCl solution.

b. Ultrasonic Studies

Various acoustic parameters have been obtained for MgCl

2

, CaCl

2

and SrCl

2

in 2% fructose in 0.01m aqueous NaCl, using ultrasonic velocity and density data (Table 1).

Adiabatic compressibility (β), defined as β = (-1/V

_m

)( V

m

/ P)

S

was obtained using the Newton- Laplace equation (8) [19],

β = 1/U

²

ρ (8)

where ρ is the density U is the ultrasonic velocity of solutions. A gradual and almost linear

decrease in adiabatic compressibility (Table-3) was observed as concentration of solute was

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increased. Due to electrostriction, the solvent molecules within the primary solvation shell of electrolytic solution are rendered incompressible moreover increasing concentration of ions results in more solvent molecules to engage in incompressible solvation spheres thereby decreasing the adiabatic compressibility [20]. Further with increase in temperature hydrogen bonding among solvent-solvent molecules decreases and thus there are more free solvent molecules available for solvation of electrolyte ions which is confirmed by decreasing values of β with increase in temperature. This decrease in adiabatic compressibility with solute concentration as well as with temperature shows presence of prominent ion-solvent interactions in the systems and these interactions increase with increase in solute concentration and with increase in temperature also.

Intermolecular free length (L

f

) was obtained from adiabatic compressibility (β) using equation (9) [21]:

L

f

= Kβ

^1/2

(9)

Where K is the temperature dependent constant (= (93.875 + 0.375T) × 10

^-8

) [22]. It is clear from table 3 that ultrasonic velocity (U) increases and intermolecular free length (L

f

) decreases with increase in concentration for all MgCl

2

, CaCl

2

and SrCl

2

in 2% fructose in 0.01m aqueous NaCl system. In general U and L

_f

have been reported to vary as the inverse of each other as in the present systems [23, 24]. The decrease in the value of L

f

with the increase in molality indicates the presence of significant ion-solvent interaction between solute and solvent molecules due to which the structural arrangement in the neighbourhood of constituent ions is considerably affected [25]. As temperature increases there is an increase of intermolecular distance, thereby increasing the distance between surfaces of two molecules and thus increasing L

f

values.

To obtain a firm impact of interactions in solutions, relative association (R

_A

) was calculated by following relation (10) [26]:

R

_A

= (ρ/ρ

₀

)(U

₀

/U)

^1/3

(10)

where ρ

0

and U

0

are the density and ultrasonic velocity of solvent respectively. Relative association is influenced by two factors (i) breaking up of the associated solvent molecules on addition of solute in it and (ii) the solvation of solute molecules. The former leads to decrease and later to increase of relative association. In the present study, the values of R

A

increase with increase in solute concentration as well as with increase in temperature showing significant ion- solvent interactions which increase with increase in solute concentration (fig 1) [27].

Specific acoustic impedance (Z), Rao’s molar sound function (R) and Molar compressibility (W) were also calculated using relations (11), (12) and (13) [28- 30]:

Z = Uρ (11)

R = (M/ρ)U

^1/3

(12) W = (M/ρ)β

^-1/7

(13)

Where M is the apparent molecular weight of the solution and can be calculated according to the following equation:

M = M

1

W

1

+ M

2

W

2

(14)

(5)

Where W

1

and W

2

are weight fractions of solvent and solute, respectively. M

1

and M

2

are molecular weights of solvent and solute, respectively.

Specific acoustic impedance (Z) increases with increase in temperature as well as with increase in concentration (fig 2) suggesting presence of solvent-solute interactions in system[31].The molar sound velocity (R) and molar compressibility (W) increase linearly with concentration (fig 3, fig 4) indicate the solute-solvent interactions in the system[31].

Another parameter studied was solvation number, obtained by relation (15) [32, 33]:

S

N

= (n

¹

/n

2

)(1-β/β

0

) (15)

Where n

₁

and n

₂

are the numbers of moles of the solvent and the solute, respectively ; β and β

₀

compressibility coefficients of the solution and the pure solvent, respectively. Considerably high solvation numbers (table-3) obtained especially at low solute concentrations and at low temperatures indicate either strong electrostriction around the chlorine ions and/or the range of the cation electrostrictive interaction, which is longer than the first solvation shell [34]. This may be because in the acoustic method, not only the inner shell molecules are compressed but up to some extent outer also and high solvation numbers are obtained in result. Solvation numbers decrease with increase in solute concentration as well as with increase in temperature for all three salts.

The dispersion of ultrasonic waves in system contains information about the characteristic time of relaxation process that causes the dispersion. The relaxation time was calculated as (16) [35- 37]:

τ = (4η/3ρU

²

) (16) where η is viscosity

^*

.

The relaxation time decreases with increase in temperature and its temperature dependence is used to calculate Gibb’s free energy of activation for relaxation process (17) [38]:

∆G

^*

= kT ln(kTτ/h) (17)

Where k is Boltzmann constant, T, the absolute temperature and h is the Planck’s constant.

* The viscosity data used for calculations is available with authors.

TABLE – 1

Densities, apparent molar volumes and ultrasonic velocities of MgCl₂, CaCl₂ and SrCl₂ in 2% fructose in 0.01m aqueous NaCl at different temperatures.

C × 10²/mol lit^-1  /g cm^-3 /cm³ mol^-1 !/m s^-1

Magnesium Chloride in 2% Fructose in 0.01m aq. NaCl

Temperature = 303.15K _" = 1.003286 gcm^-3 !_" = 1516.62 m s^-1

1.0023 1.004312 100.60 1518.02

2.0024 1.005252 104.77 1519.34

3.9954 1.006971 110.71 1521.73

5.9783 1.008545 114.95 1523.49

7.9505 1.009978 118.74 1526.35

9.9115 1.011305 121.99 1528.04

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11.8604 1.012476 125.40 1530.34 Temperature = 308.15K _" = 1.001621 gcm^-3 !_"= 1527.31 m s^-1

1.0006 1.002609 104.39 1528.41

1.9989 1.003516 108.32 1529.67

3.9884 1.005205 113.26 1531.98

5.9676 1.006740 117.33 1533.82

7.9363 1.008171 120.57 1536.57

9.8937 1.009487 123.59 1538.24

11.8399 1.010728 126.18 1540.67

Temperature = 313.15K _" = 0.999713 gcm^-3 !_"= 1536.77 m s^-1

0.9986 1.000675 107.00 1537.28

1.9950 1.001564 110.55 1538.49

3.9805 1.003215 115.35 1540.71

5.9557 1.004725 119.18 1542.51

7.9203 1.006142 122.16 1545.28

9.8737 1.007448 125.00 1546.88

11.8159 1.008676 127.48 1549.41

0.9965 0.998556 109.03 1544.59

1.9908 0.999434 112.15 1545.82

3.9719 1.001061 116.79 1547.97

5.9428 1.002556 120.43 1549.75

7.9029 1.003935 123.61 1552.56

9.8522 1.005251 126.09 1554.09

11.7901 1.006479 128.42 1556.64

Calcium Chloride in 2% Fructose in 0.01m aq. NaCl

1.0031 1.004539 22.03 1518.17

2.0055 1.005674 27.85 1519.18

4.0073 1.007726 36.10 1521.12

6.0045 1.009577 42.11 1522.27

7.9959 1.011239 47.40 1525.32

9.9807 1.012746 52.07 1526.13

11.9585 1.014119 56.25 1528.54

1.0013 1.00281 28.23 1528.55

2.0019 1.003897 33.27 1529.46

4.0000 1.005885 40.36 1531.30

5.9933 1.007689 45.70 1533.03

7.9808 1.009330 50.34 1535.69

9.9623 1.010876 54.03 1536.44

11.9362 1.012232 58.03 1538.66

Temperature = 313.15K _" = 0.999713gcm^-3 !_"= 1536.77 m s^-1

0.9994 1.000856 32.66 1537.44

1.9979 1.001906 37.27 1538.25

3.9919 1.003832 43.85 1540.02

5.9808 1.005592 48.74 1541.71

7.9639 1.007191 53.14 1544.52

9.9407 1.008689 56.74 1545.07

11.9108 1.010079 60.00 1547.37

0.9973 0.998726 35.60 1544.84

1.9936 0.999752 39.87 1545.58

3.9831 1.00164 46.05 1547.26

5.9676 1.003369 50.70 1549.01

7.9462 1.00496 54.70 1551.94

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TABLE-2

Limiting apparent molar volume

φ

^o_v^{, S}V and apparent molar volume expansibility (_#^") of MgCl₂, CaCl₂ and SrCl₂ in 2% fructose in 0.01m aqueous NaCl at different temperatures, standard errors are given in

parenthesis.

9.9186 1.006443 58.14 1552.31

11.8837 1.00778 61.62 1554.71

Strontium Chloride in 2% Fructose in 0.01m aq. NaCl

1.0018 1.004492 145.76 1517.46

2.0005 1.005597 150.61 1518.05

3.9879 1.007611 157.65 1520.35

5.9612 1.009430 163.02 1521.67

7.9197 1.011078 167.68 1523.35

9.8630 1.012592 171.70 1524.96

11.7909 1.014008 175.11 1526.51

1.0001 1.002776 150.89 1527.76

1.9970 1.003842 155.15 1528.33

3.9808 1.005801 161.35 1530.51

5.9504 1.007597 165.92 1531.79

7.9053 1.009241 169.95 1533.4

9.8450 1.010752 173.59 1534.92

11.7694 1.012162 176.77 1536.4

0.9982 1.000834 154.36 1537.05

1.9931 1.001866 158.64 1538.25

3.9728 1.003781 164.27 1539.14

5.9382 1.005531 168.69 1540.36

7.8888 1.007131 172.64 1541.93

9.8244 1.008637 175.84 1543.38

11.7447 1.010041 178.73 1544.08

0.9961 0.998713 156.65 1543.74

1.9889 0.999729 160.66 1544.29

3.9642 1.001618 166.01 1546.29

5.9253 1.003341 170.37 1547.48

7.8714 1.004915 174.28 1549.03

9.8025 1.006382 177.60 1550.41

11.7185 1.007783 180.27 1551.7

Electrolyte T/K ^o

φ

v ^/cm³^mol^-1 ^S^v^/cm³^l^1/2^mol^-3/2 ^#^"^/cm³^mol^-1^K^-1

MgCl₂ 303.15 90.51 (±0.190) 1.005 (±0.007) 1.214

MgCl₂ 308.15 95.58 (±0.111) 0.888 (±0.004) 0.934

MgCl₂ 313.15 98.66 (±0.836) 0.836 (±0.002) 0.653

MgCl₂ 318.15 100.92 (±0.799) 0.799 (±0.004) 0.373

CaCl₂ 303.15 8.15 (±0.090) 1.389 (±0.003) 2.146

CaCl₂ 308.15 16.17 (±0.148) 1.205 (±0.006) 1.696

CaCl₂ 313.15 21.48 (±0.075) 1.115 (±0.003) 1.246

CaCl₂ 318.15 24.95 (±0.137) 1.054 (±0.005) 0.796

SrCl₂ 303.15 135.51 (±0.108) 1.212 (±0.004) 1.560

SrCl₂ 308.15 140.13 (±0136) 1.063 (±0.005) 1.140

SrCl₂ 313.15 144.36 (±0.107) 1.001(±0.004) 0.720

SrCl₂ 318.15 146.77 (±0.205) 0.975(±0.008) 0.300

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TABLE-3

Adiabatic compressibility (β), inter molecular free length (L_f), relative association (R_A), Rao’s molar sound function (R), specific acoustic impedance (Z), molar compressibility (W) and solvation number (S_N)

for MgCl₂, CaCl₂ and SrCl₂in 2% fructose in 0.01m aqueous NaCl at different temperatures.

C×10²

/mol lit^-1 β×10^-10/Pa^-1 L_f×10^-11/m S_N

Magnesium Chloride in 2% Fructose in 0.01m aqueous NaCl Temperature = 303.15 K β₀ = 4.3302 Pa^-1

1.0023 4.3209 4.3144 15.8825

2.0024 4.3094 4.3087 15.3259

3.9954 4.2885 4.2982 14.3381

5.9783 4.2719 4.2899 13.0959

7.9505 4.2499 4.2788 13.3472

9.9115 4.2350 4.2713 12.5927

11.8604 4.2173 4.2624 12.3717

Temperature = 308.15 K β₀ = 4.2814 Pa^-1

1.0006 4.2696 4.3275 13.4393

1.9989 4.2587 4.3220 13.7721

3.9884 4.2388 4.3118 13.3555

5.9676 4.2222 4.3034 12.4916

7.9363 4.2011 4.2926 12.7821

9.8937 4.1865 4.2852 12.1155

11.8399 4.1682 4.2758 12.0747

0.9986 4.2286 4.3452 9.0086

1.9950 4.2182 4.3399 11.3118

3.9805 4.1992 4.3301 11.8991

5.9557 4.1831 4.3218 11.4448

7.9203 4.1622 4.3110 11.9973

9.8737 4.1482 4.3037 11.4300

11.8159 4.1297 4.2941 11.5516

0.9965 4.1976 4.3677 16.9833

1.9908 4.1872 4.3623 15.3150

3.9719 4.1688 4.3527 13.7207

5.9428 4.1531 4.3444 12.6103

7.9029 4.1324 4.3336 12.8671

9.8522 4.1188 4.3265 12.0763

11.7901 4.1003 4.3168 12.0937

Calcium Chloride in 2% Fructose in 0.01m aqueous NaCl Temperature = 303.15 K β₀ = 4.3321 Pa^-1

1.0031 4.3191 4.3135 18.2250

2.0055 4.3085 4.3082 15.9024

4.0073 4.2887 4.2983 14.2662

6.0045 4.2744 4.2912 12.5676

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7.9959 4.2503 4.2791 13.2777

9.9807 4.2395 4.2736 12.0082

11.9585 4.2204 4.2640 12.0421

1.0013 4.2680 4.3267 15.5617

2.0019 4.2583 4.3217 14.0618

4.0000 4.2397 4.3123 13.0647

5.9933 4.2225 4.3036 12.4112

7.9808 4.2011 4.2926 12.7843

9.9623 4.1905 4.2872 11.5907

11.9362 4.1729 4.2782 11.5685

0.9994 4.2270 4.3444 11.1624

1.9979 4.2181 4.3398 11.3930

3.9919 4.2004 4.3307 11.5127

5.9808 4.1838 4.3221 11.2850

7.9639 4.1620 4.3108 12.0369

9.9407 4.1529 4.3061 10.8264

11.9108 4.1348 4.2968 10.9901

0.9973 4.1955 4.3666 19.7247

1.9936 4.1872 4.3623 15.3413

3.9831 4.1702 4.3534 13.2574

5.9676 4.1537 4.3447 12.4802

7.9462 4.1314 4.3331 13.0192

9.9186 4.1234 4.3289 11.4764

11.8837 4.1052 4.3193 11.5588

Strontium Chloride in 2% Fructose in 0.01m aqueous NaCl Temperature = 303.15 K β₀ = 4.3314 Pa^-1

1.0018 4.3233 4.3156 12.7914

2.0005 4.3152 4.3116 11.5842

3.9879 4.2936 4.3008 12.7188

5.9612 4.2784 4.2932 11.7155

7.9197 4.2620 4.2849 11.4090

9.8630 4.2467 4.2772 11.0925

11.7909 4.2321 4.2699 10.7945

1.0001 4.2725 4.3290 9.6522

1.9970 4.2648 4.3251 9.8286

3.9808 4.2444 4.3147 11.5315

5.9504 4.2297 4.3072 10.8505

7.9053 4.2140 4.2992 10.6899

9.8450 4.1994 4.2917 10.4478

11.7694 4.1854 4.2846 10.2104

Temperature = 313.15 K β₀ = 4.2410Pa^-1

0.9982 4.2292 4.3455 8.2312

1.9931 4.2183 4.3399 11.2827

3.9728 4.2054 4.3333 9.8698

5.9382 4.1914 4.3261 9.6282

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7.8888 4.1762 4.3182 9.7055

9.8244 4.1622 4.3109 9.6066

11.7447 4.1526 4.3060 9.0481

0.9961 4.2016 4.3697 11.7731

1.9889 4.1943 4.3660 10.6681

3.9642 4.1756 4.3562 11.5035

5.9253 4.1620 4.3491 10.6504

7.8714 4.1472 4.3413 10.4301

9.8025 4.1337 4.3343 10.1112

11.7185 4.1211 4.3277 9.8100

TABLE-4

Relaxation time (τ) and Gibb’s free energy of activation (∆G^*) of MgCl₂, CaCl₂ and strontium chloride (SrCl₂) 2% fructose in 0.01m aqueous NaCl at different temperatures.

Concentration C × 10²/mol lit^-1

Relaxation time τ×10^-13/s

Gibb’s free energy of activation

∆G^*× 10^-21/J mol^-1

Magnesium Chloride in 2% Fructose in 0.01m aqueous NaCl Temperature = 303.15K

1.0023 4.8845 4.7114

2.0024 4.8920 4.7179

3.9954 4.9003 4.7250

5.9783 4.9081 4.7316

7.9505 4.9076 4.7312

9.9115 4.9130 4.7358

11.8604 4.9131 4.7359

Temperature = 308.15K

1.0006 4.3342E-13 4.3504

1.9989 4.3408 4.3569

3.9884 4.3484 4.3643

5.9676 4.3550 4.3707

7.9363 4.3546 4.3704

9.8937 4.3591 4.3748

11.8399 4.3586 4.3743

0.9986 3.8751 4.0067

1.9950 3.8811 4.0134

3.9805 3.8879 4.0210

5.9557 3.8936 4.0273

7.9203 3.8928 4.0265

9.8737 3.8977 4.0318

11.8159 3.8965 4.0306

0.9965 3.5094 3.7050

1.9908 3.5143 3.7112

3.9719 3.5202 3.7185

5.9428 3.5255 3.7251

7.9029 3.5244 3.7238

9.8522 3.5288 3.7292

11.7901 3.5281 3.7284

Calcium Chloride in 2% Fructose in 0.01m aqueous NaCl Temperature = 303.15K

1.0031 4.8465 4.6787

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2.0055 4.8555 4.6865

4.0073 4.8670 4.6965

6.0045 4.8787 4.7065

7.9959 4.8758 4.7040

9.9807 4.8860 4.7127

11.9585 4.8850 4.7119

1.0013 4.3007 4.3174

2.0019 4.3092 4.3258

4.0000 4.3194 4.3359

5.9933 4.3265 4.3429

7.9808 4.3267 4.3431

9.9623 4.3363 4.3525

11.9362 4.3370 4.3532

0.9994 3.8453 3.9734

1.9979 3.8532 3.9823

3.9919 3.8623 3.9924

5.9808 3.8685 3.9993

7.9639 3.8675 3.9983

9.9407 3.8776 4.0095

11.9108 3.8776 4.0095

0.9973 3.4824 3.6711

1.9936 3.4895 3.6800

3.9831 3.4974 3.6900

5.9676 3.5028 3.6968

7.9462 3.5012 3.6948

9.9186 3.5108 3.7067

11.8837 3.5108 3.7067

Strontium Chloride in 2% Fructose in 0.01m aqueous NaCl Temperature = 303.15K

1.0018 4.8881 4.7145

2.0005 4.9002 4.7249

3.9879 4.9092 4.7326

5.9612 4.9199 4.7417

7.9197 4.9264 4.7471

9.8630 4.9312 4.7513

11.7909 4.9363 4.7556

1.0001 4.3379 4.3540

1.9970 4.3484 4.3643

3.9808 4.3567 4.3725

5.9504 4.3665 4.3820

7.9053 4.3726 4.3880

9.8450 4.3779 4.3931

11.7694 4.3829 4.3979

0.9982 3.8766 4.0083

1.9931 3.8823 4.0147

3.9728 3.8958 4.0298

5.9382 3.9044 4.0393

7.8888 3.9098 4.0452

9.8244 3.9154 4.0514

11.7447 3.9235 4.0603

0.9961 3.5133 3.7099

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1.9889 3.5211 3.7196

3.9642 3.5278 3.7280

5.9253 3.5355 3.7376

7.8714 3.5405 3.7438

9.8025 3.5456 3.7500

11.7185 3.5506 3.7563

0 2 4 6 8 10 12

1.000 1.001 1.002 1.003 1.004 1.005 1.006 1.007 1.008 1.009

MgCl₂ CaCl₂ SrCl₂

RA

C×10² (mol lit^-1)

Figure 1 Variation of relative association (R_A) with molar concentration (C) for magnesium chloride, calcium chloride and strontium chloride in 2% fructose in 0.01m aqueous NaCl at 303.15K.

0 2 4 6 8 10 12

2.052 2.054 2.056 2.058 2.060 2.062 2.064

R×104 [m3 mol-1 (ms-1 )1/3 ]

C×10² (mol lit^-1)

MgCl₂ CaCl₂ SrCl

2

Figure 2 Variation of molar sound velocity (R) with molar concentration (C) for magnesium chloride, calcium chloride and Strontium chloride in 2% fructose in 0.01m aqueous NaCl at 303.15K.

The relaxation time increases with increase in concentration of solute and decreases with

increase in temperature (Table 4). The values of ∆G

^*

are almost constant with increase in

temperature. The constant values of ∆G

^*

suggest that the rearrangement of molecules in solution

are characteristic of physical properties of solute only [37].

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0 2 4 6 8 10 12 1.520

1.525 1.530 1.535 1.540 1.545 1.550

MgCl

2

CaCl₂ SrCl₂

Z×10-6 (kg m-2 s-1 )

C×10² (mol lit^-1)

Figure 3 Variation of specific acoustic impedance (Z) with molar concentration (C) for magnesium chloride, calcium chloride and Strontium chloride in 2% fructose in 0.01m aqueous NaCl at 303.15K.

0 2 4 6 8 10 12

3.891 3.894 3.897 3.900 3.903 3.906 3.909

MgCl₂ CaCl₂ SrCl₂

W× 104 (m3 mol-1 Pa1/7 )

C×10² (mol lit^-1)

Figure 4 Variation of molar compressibility (W) with molar concentration (C) for magnesium chloride, calcium chloride and Strontium chloride in 2% fructose in 0.01m aqueous NaCl at 303.15K.

CONCLUSION

It has been found that 2% fructose in 0.01 m aqueous NaCl behaves as a solvent similar to water.

The positive values of φ

^o_v

, decrease in adiabatic compressibility, increase in intermolecular free

length, increase of relative association show presence of ion-solvent interactions of MgCl

2

,

CaCl

2

and SrCl

2

with 2% fructose in 0.01m aqueous NaCl as solvent. Acoustic parameters as

specific acoustic impedance, Rao’s molar sound function, molar compressibility, solvation

number were reported. Characteristic time of relaxation was obtained and used to get Gibb’s free

energy of activation for relaxation process. The decrease in φ

^o_E

values with increase in

temperature shows absence of ‘caging effect’, the negative sign of ( ∂

²

φ

^ov

/ ∂ T

²

)

p

suggests that

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MgCl

2

, CaCl

2

and SrCl

2

act as structure-breaker in 2% fructose in 0.01m aqueous NaCl as solvent.

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