Download 1. introduction

1.
INTRODUCTION
1.1ABSTRACT
To study of physical properties like viscosities, densities of aliphatic and aromatic ketones and
their binary mixture with polar and non-polar solvents are receiving attention in chemistry
because of their importance in industrial processes. These physical properties involve challenges
of interpreting the excess quantities as a means of understanding the nature of intermolecular
interaction among the binary mixture. From ideal behavior of some physical properties and study
of characteristic departure, the interaction between molecules can be found out.
In the present work, liquid mixtures of ketones with polar & non polar solvents and
thermodynamic properties like densities and viscosities of will be measured over a complete
range of composition at three different temperatures 298.15, 303.15 and 308.15 K and at
atmospheric pressure. From these values of densities and viscosities, molar excess volume VE,
deviation in viscosity ∆η will be calculated.
The first system study the physical properties like density ρ viscosity η of propan-2-one with
methanol, ethanol, benzene and toluene at three different temperatures are measured and
evaluated. The excess thermodynamics properties molar excess volume V E , deviation in
viscosity η E , viscous flow of excess Gibb’s free energy ∆GE of propan-2-one with methanol,
ethanol, benzene and Toluene at three different temperatures are measured and evaluated, The
sign of excess properties assessing the extent of molecular interaction and the compactness due
to molecular arrangement. The change in mole fraction of mixture reasonable qualitative
explanation for the behavior of mixture in present study has been suggested.
The second system study the physical properties like density ρ, viscosity η, of butan-2-one with
methanol, ethanol, benzene and toluene at three different temperatures and at atmospheric
pressure are measured and evaluated. The excess thermodynamics properties molar excess
volume V E , Excess viscosity η E , viscous flow of excess Gibb’s free energy ∆GE of butan-2-one
with methanol, ethanol, benzene and Toluene at three different temperatures are measured and
evaluated, The sign of excess properties assessing the extent of molecular interaction and the
compactness due to molecular arrangement. The change in mole fraction of mixture reasonable
qualitative explanation for the behavior of mixture in present study has been suggested
The third system study the physical properties like density
ρ᾿ viscosity
η
of acetophenone
with methanol, ethanol, benzene and toluene at three different temperatures are measured and
evaluated. The excess thermodynamics properties
molar excess volume V E ,deviation in
viscosity η E ,viscous flow of excess Gibb’s free energy ∆GE of acetophenone with methanol,
ethanol, benzene and Toluene at three different temperatures are measured and evaluated, The
sign of excess properties assessing the extent of molecular interaction and the compactness due
to molecular arrangement. The change in mole fraction of mixture reasonable qualitative
explanation for the behavior of mixture in present study has been suggested.
The fourth system study the physical properties like density ρ viscosity η of propiophenone with
methanol, ethanol, benzene and toluene at three different temperatures are measured and
evaluated. The excess thermodynamics properties molar excess volume V E , deviation in
viscosity η E viscous flow of excess Gibb’s free energy ∆GE of propiophenone with methanol,
ethanol, benzene and Toluene at three different temperatures are measured and evaluated. The
sign of excess properties assessing the extent of molecular interaction and the compactness due
to molecular arrangement, the change in mole fraction of mixture reasonable qualitative
explanation for the behavior of mixture in present study has been suggested.
1.2 INTRODUCTION
The liquid state of matter is intermediate between the gaseous and the solid states. The
antiparticle spaces in this state are less as compared to the gaseous state and more in comparison
with the solid state. As a result, the properties of the liquids are expected to be intermediate with
respect to the other two states of matter. It may be noted that like gases, liquids have also certain
characteristics common to all of them. These are definite volume but no definite shape,
incompressibility, diffusion evaporation, viscosity, surface tension etc. These properties of the
liquids are based on a theory called kinetic molecular theory. The main postulates of the theory
are
i. Liquids are composed of particles called molecules.
Ii. The inter molecular forces of attraction among the molecules in a liquid are quite appreciable.
iii. As compared to the gas, the molecules in a liquid are relatively close to each other.
iv. The molecules are in constant random motion.
v. The average kinetic energy of molecules in a liquid is directly proportional to temperature.
Let us discuss the important properties associated with the liquids.
The physical properties of substance are those which could study and determine without causing
any chemical change in it, the basic physical properties of liquid are density, viscosity, solubility,
Vapor pressure, surface Tension, Refraction etc. The flow is characteristic property of liquid. All
these physicals properties related to each other there is need to discuss properties and there
relations.
Volume:A liquid has a definite volume but no definite shape. It always maintains its volume whatever
may be the shape and size of the container. Thus, liquid is different from the gas because gas
does keep its volume. Moreover the liquid remains confined to the lower part of the container in
which it is placed while a gas remains distributed throughout the container. This behavior of the
liquid is due to the reason the molecules are quite close to one another and intermolecular forces
of attraction are stronger as compared to the gas. Thus, the molecules in a liquid are not free to
occupy any volume available to them.
Density:Since the molecules in the liquid state are more closely packed as compared to the gaseous
state, the density in this state of matter is expected to be higher as compared to the gaseous state
under a given temperature and pressure. For example, at 373 K and under 1 atm pressure, the
density of water is 0-958 g/cm3 while that of water vapours under similar conditions is 0 000588
g/cm3. This means that the density in the liquid state of water is about 1000 times higher as
compared to the gaseous state.
Compressibility:Liquids are much less compressible than the gases because the intermolecular distances are
less as compared to the gases. Therefore, when pressure is increased, there is a very little scope
for the molecules to come closer or the liquids are almost incompressible.
Diffusion:Diffusion is the movement of the solute particles from a higher concentration to the lower
concentration in a particular medium, like gases, molecules in the liquids also diffuse but at a
slower rate. This is quite expected also because in the liquids the molecules are quite close and
there is comparatively less scope for the movement of the molecules.
In order to compare the rates of diffusion in the liquids and gases, take two jars. Fill one of
them with water. Introduce a drop of liquid bromine in both the jars and cover them with discs.
Now, observe the movement of bromine in air as well as in water. In the jar containing air, the
liquid drop vaporizes and immediately spreads throughout the jar. But in the jar containing
water, the drop spreads slowly and only after sometime the water in the jar becomes uniformly
colored. This clearly shows that liquids diffuse at a slower rate as compared to the gas.
Evaporation:Evaporation may be defined as the process of conversion of a liquid into its vapours at room
temperature.
The process of evaporation can be explained with the help of kinetic molecular theory for
the liquids. We know that the molecules in a given liquid are in a state of constant motion and
possess certain kinetic energy as well. Although the average kinetic energy of the molecules is
expected to remain constant at a given temperature (say room temperature), but just as in gases,
all the molecules do not have the same kinetic energy. It may vary from very small to very high
value. As a result, a certain fraction of the molecules present the surface of the liquid will have
kinetic energies large enough to overcome the attractive forces of the neighboring molecules.
Therefore; they will escape into the space above the liquid surface and will appear as vapours.
This will also apply to the rest of molecules on the surface. If the liquid is kept in an open vessel,
the evaporation will continue till it is complete.
It is a common experience that cooling is caused during evaporation. Actually, during
evaporation, the molecules having higher kinetic energy escape from the surface of the liquid.
Therefore, the average kinetic energy of the rest of the molecules decreases. Since the
temperature of the liquid is proportional to the average kinetic energy, it gets lowered. Therefore,
cooling is caused during evaporation.
Factors Affecting Rate of Evaporation:Although evaporation is common to all the liquids but they don’t evaporate at the same rate, the
rate of evaporation of a liquid depends upon the following factors:
(i)
Nature of the liquid :- The rate of evaporation is closely linked with the nature of the
liquid i.e., with the magnitude of the intermolecular forces of attraction. Greater the magnitude of
such
forces,
lesser
will
be
the
rate
of
evaporation. In general, non polar liquids evaporate faster than the polar liquids because
attractive forces in them are less. For example, diethyl ether (ether) evaporates at a faster rate
than ethyl alcohol (alcohol) which shows that attractive forces in the molecules of ether are
weak.
(ii)
Temperature :- As the temperature of a liquid increases, its evaporation becomes faster.
The rise in temperature increases the average kinetic energy of the molecules. As a result, greater
number
of
molecules
will
have
energy
needed to overcome the attractive forces of the neighboring molecules. In other words, the
number of molecules escaping from the surface of the liquid will also become more leading to
faster evaporation.
(iii) Surface
area :- The rate of evaporation is also related to the surface area of the liquid. Since
the evaporation takes place from the surface of the liquid, more the area available, greater will be
the evaporation.
VAPOUR PRESSURE:All liquids exhibit tendency for evaporation, Evaporation takes place at the
surface of liquid. If the kinetic energy of liquid molecules overcomes the intermolecular force of
attraction in the liquid state then the molecule from the surface of liquid escapes into the space
above the surface. The process is called evaporation. If the process of evaporation is carried out
in a closed container then the vapors of liquid remain in contact with the surface of liquid. Like
gas molecules vapors of liquid molecules also execute continuous random motion. During this
motion, molecules collide with the walls of the container and each other, lose their energy and
return back to liquid state. This process is called continuous processes. Hence after some time
equilibrium is established, at constant temperature between evaporation and condensation. At
equilibrium number of molecules in vapour state remains constant at constant temperature. The
pressure exerted by the vapours of liquid on the surface of liquid at equilibrium called vapour
pressure of liquid.
The vapour pressure of the liquid related on the type of the liquid and the
temperature with increase of intermolecular forces of attraction vapour pressure of liquid
decreases and with rise of temperature vapour pressure of liquid increases, Mercury manometer
may be used to determine vapour pressure of liquid. Vapour pressure effect viscosity of liquids.
Factors Affecting Vapours Pressure:The vapour pressure of a liquid depends mainly upon two factors. These are the nature of
the liquid and the temperature.
Nature of the Liquid:The vapour pressure of a liquid is linked with its nature i.e., magnitude of the
intermolecular forces present in its molecules. When these forces are weak, the molecules will
readily change into vapours and the equilibrium vapour pressure will be high. However, if these
forces are strong, then the molecules will not change into vapours so readily and consequently
the vapour pressure will be comparatively low. From the curves listed in the Fig. 5.22, it is quite
clear that at a particular temperature, the vapour pressure of diethyl ether is the maximum while
that of water is the minimum. Thus, the vapour pressure predicts the magnitude of the
intermolecular forces. Higher the vapour pressure of a particular liqiud, lesser will be the
magnitude of these forces.
Temperature of the Liquid:The vapour pressure of a liquid increases with the rise in temperature. When the
temperature is increased, the average kinetic energy of the molecules in the liquid also increases.
As a result, the number of molecules having sufficient kinetic energy to overcome the
intermolecular forces of attraction also increases. This will lead i a greater number of molecules
in the vapour phase and consequently the vapour pressure of the liquid will increase.
SURFACE TENSION:Surface tension is a characteristic property of liquid state. Gaseous or solid state
do mot exhibit this property consider a beaker containing a liquid. The molecule in the bulk of
liquid is surrounded equally by other neighboring molecules of the liquid. Hence the molecule in
the bulk is attracted from all the sides exerted by surrounding molecules. Hence all the equal and
opposite forces are cancelled and there is no resultant force of attraction acting on the molecule.
However in case of the molecules at the surface of liquid, there are molecules of liquid below it.
But there are no molecules of liquid above it. Hence on the surface, liquid molecules experience
force of attraction in the downward direction toward bulk of the liquid.
There are no forces of attraction in the upward direction. Therefore surface of the
liquid is always under tension and behaves as a stretched membrane and tends to contract.
Therefore liquid drop acquires shape that has minimum surface area. For a given mass of liquid
spherical shape is with a minimum surface area. Therefore mercury droplets and water droplets
are spherical. If an attempt is made to increase surface area of liquid then the molecules from the
bulk of the liquid experiencing equal pulls from all sides must be brought to the surface. For
doing this additional amount of work has to be done, when water is heated thermal energy of the
molecules increase. The water molecules then overcome intermolecular force of attraction come
to the surface and then escape from the surface. It is measured in the unit of kg s-2 expressed as
Nm-1
Factors Affecting the surface tension of a liquid:- The property of capillary action due to which
liquid rises or even sinks in capillary is due to surface tension. Surface tension decreases with
rise of temperature. Soaps and detergents are used for cleaning clothes and utensils because they
reduce surface tension of water. Fine droplets are formed which remove oil and dust from
clothes and utensils, Surface tension effect viscosity of liquids.
(i) Temperature of the liquid:Surface tension decreases with rise in temperature. As the temperature of the liquid
increases, the average kinetic energy of molecules presents increases. This results in decrease
in the intermolecular forces of attraction also and decreases in the value of surface tension. At
a certain temperature known as critical temperature, the surface tension of the liquid
becomes zero which means that the meniscus between the liquid and the vapours disappears.
(ii)
Nature of the liquid:The surface tension of a liquid is linked with the intermolecular forces of
attraction present in the molecules of a particular liquid. Greater the magnitude of such forces
more will be the value of surface tension. The surface tension for a few liquids in m N-1 is as
follows:
Water (72-8) > Ethyl alcohol (22-3) > Ether (17-0)
Important Consequences of Surface Tension:-
'A few important consequences of surface tension are discussed.
Spherical shape of liquid drops:The spherical shape of the liquid drops is because of surface tension. It tries to decrease the
surface of a liquid to the minimum. Since the sphere has the minimum surface area for a
particular volume of the liquid, the liquid drops are spherical in shape.
Insects can walk on the surface of water:We often see that small insects like flies can walk on the surface of water without
drowning. This is possible on account of surface tension as a result of which water behaves like
an elastic membrane. Therefore, insects are in a position to walk without drowning.
Capillary action:If a capillary tube is dipped in a liquid like water which wets glass, the liquid rises into a
capillary tube to a certain height. This is known as capillary action. This action is because of
surface tension. The inward pull acting on the surface molecules pushes the liquid into the
capillary tube (Fig. 5.26). The capillary action is also responsible for the rise of oil in the wick of
an oil lamp and of water below the surface of the earth in the plants through their roots.
Meniscus of a liquid:When a liquid is kept in a container, its surface acquires a curved shape known as
meniscus. Most of the liquids including water have concave meniscus. However, mercury
behaves differently. The meniscus is of convex nature. The shape of a particular meniscus can be
explained on the basis of forces of cohesion and adhesion. The former are present in the
molecules of the same type while the latter exist in the molecules of different type. When water
is taken in a container such a glass tube the adhesive forces present in the molecules of glass and
water are stronger as compared to cohesive forces in the molecules of water. This compels or
forces the surface of water to acquire a concave shape. In case of mercury, reverse happens i.e.,
cohesive forces are more than the adhesive forces. As a result, the surface of mercury acquires a
convex shape.
Rounding edges of a glass on melting:Upon heating, a glass melts and the surface of the liquid tends to take rounded shapes at
the edges. This happens in order to have minimum surface area and to minimum surface tension.
This is called fire polishing of glass.
VISCOSITY:Water and many liquids are transported from one place to other places through
pipes of different sizes. When liquid flows, it is believed to be moving in different layers. In
between the adjacent layers of liquids there is a force of friction which opposes the motion of the
layers of liquid.
The force of friction between layers of liquid is called viscosity. Viscosity is the found resistance
of liquid to flow. The lower most layer, in contact with the surface, experience maximum friction
and is almost stationary. Each layer above that experience little less friction, hence velocity goes
on increasing.
Thus viscosity of consecutive layers deceases and speed increases. Viscosity is measured in
the units of viscosity coefficient η. It has unit of poise i.e. Newton second per square meter,
Nsm-2.
If the viscosity is higher than the liquid move slowly Hydrogen bonding and strong
intermolecular interaction increase the viscosity of liquid. Glass is the example of highly viscous
liquid, Appears as solid viscosity of liquids decreases with increase of temperature.
Viscosity is a physical property of all liquids. Viscosity is a measure of the internal friction to
flow. Viscosity is affected by temperature and pressure. As temperature and pressure of liquid
and gases changes viscosity also changes.
1-2
Viscosity is two types, Absolute or dynamic viscosity and Kinematic viscosity.
Absolute viscosity measure the tangential force per unit area between layers of liquids which
results. In case of more viscous the fluid, the larger is velocity change between the layer of the
liquid because the larger the area of contact between layers of liquids which results increase in
tangential force.
Thus viscosity of fluid is defined as the measure of how resistive the fluid is to flow, in
mathematical equation of viscosity of liquid can be explained as.
Shear stress = η
Where the dynamic viscosity is η
Where shear stress is σ and strain rate is e
Then the expression become σ = η e
Strain rate is e = v/x
Where x
η=σ
is length and v is velocity therefore dynamic viscosity is written as
v
x
Kinematic viscosity is calculated to dividing density by the dynamic viscosity.
u =
η/ρ
Common units of viscosity are poise (p), stokes (st),
And In the SI system international d unit’s, N.S/m 2 , Pa.s or Kg/m.s. are the units of dynamic
viscosity. Where N is Newton and Pa is Pascal.
1 Pa.s = 1. N.S/m 2 =1 Kg/m.s
In CGS system, The dynamic viscosity is
1 poise = dyne ' s / cm 2 = g / cm.s = 1/10 pa.s
Centipoises (cp) are most convenient unit. It is 1/100 of poise.
For SI system, units of Kinematic viscosity is stokes (st) or saybolt second universal (ssu) units.
The kinematic viscosity is expressed m 2 /s or stokes (st).
1st = 10-4 m 2 /s
1 st= 100 cSt.
1 cSt = 10-6 m 2 /s
At 20.20 0C, specific gravity of water is one and therefore At 20.20 0C, the kinematic viscosity
of water is also 1.0cSt.
The flow is characteristics property of liquid which dependent on the viscosity having two types
1-5
Newtonian liquids and Non-Newtonian liquids.
Newtonian liquids:-Those liquids in which viscosity remains constant and not depend on the
shear stress.
Non-Newtonian liquids:- Those liquids in which viscosity based on the applied shear force and
does not remains constant.
The Non-Newtonian liquids are of two types Non-Newtonian time independent liquids and NonNewtonian time dependent liquids.
The Non-Newtonian time dependent liquids in which viscosity dose not remains constant and
based on the applied shear force and time,
The liquids in which viscosity dose not remains constant and depends on only applied shear
force and not on time termed as Non-Newtonian time independent liquids.
Non Newtonian time independent liquids, these types of fluids are pseudo plastic liquid, Dilatant
liquid and Bingham plastic.
In pseudo plastic liquid an increasing shear rate which cause decreasing viscosity they are called
shear thinning. Dilatant liquid these liquids as shear rate increase viscosity of liquid also increase
called as shear thicken liquids. Bingham plastic liquid in which shear rate is zero.
.
Fig1.1:- Types of Non Newtonian time independent liquids
Non Newtonian time dependent liquid where viscosity changes with time and constant shear
force, this type of includes Thixotropic fluid and Rheopectic fluid.
Thixotropic fluid in which viscosity goes on decreasing with time as constant share force,
Rheopectic fluid in which viscosity goes on increasing with time as constant share rate.
Fig1. 2:-Types of Non- Newtonian time dependent liquids.
This information and other understanding is use full to known about different type of interaction
among different molecules. Related to viscosity very large number of theoretical, experimental
and analytic investigation is carried out.
All liquid pusses ‘characteristic property that is flowing under an applied force, these force of
their own weight, When a liquid flows through a tube, the liquid layer in contact with the wall of
the tube is stationary whereas. The centre layer has the minimum velocity and the intermediate
layers have gradation of velocities.
Similarly when liquid flowing over a glass plate. The layer which in contact with glass plate is
stationary, While velocity of the different layer increases with increasing distance from surface,
The layer which have high velocity with free surface of liquid. On basis of this relative motion of
each layer develops frictional force and it is being dragged in backward direction and work has
to be done to maintain the flow. Thus internal friction which resists the relative motion of liquid
termed as viscosity.
There is many theory of viscosity but important theory given by Newton. According Newton
theory when liquid flow, the layers of liquid move at different velocities and liquid viscosity
arise due to shear stress between moving layers that oppose applied force.
Fig.1.3:-
Laminar shear of fluid between two plates
These Newton stated that following relations, between shear stress and velocity
gradient.
τα
du
dy
τ =υ
du
dy
Whereas τ is shear stress, υ is coefficient of viscosity and
du
is velocity gradient,
dy
Many fluids show such type of relation termed as Newtonian fluid when non-Newtonian
fluid has complicated relationship shear stress and velocity gradient.
Factors affecting on the viscosity of liquids
1. Molecular weight increase viscosity increase that related to density. Molecular weight directly
proportional to density as the density increase distance between liquid molecule decreases. That
result cohesive forces between molecules increase and viscosity of liquid increase.
2. Branched chain compounds have higher viscosity than strain chain compounds in branched
chain compound cohesive forces between molecules increase and viscosity of liquid increase.
3. The polar compounds are more viscosity than non polar compounds in polar compounds
cohesive force attributed to the presence of different type of intermolecular forces which result
increase in viscosity.
4. The viscosity of pure solvent is lower than viscosity of solution. Added solute increases the
viscosity of solvent.
5. Temperature increase viscosity decrease as temperature increases kinetic energy of molecule
increase, cohesive forces decrease and molecular movement increase which result decrease in
viscosity.
6. Pressure increases viscosity increase at high pressure on liquid cohesive forces increase and
movement of molecule decrease which result of that viscosity increase.
7. The liquids having stronger intermolecular forces Of attraction are expected to have more viscosities than
[lie liquids with weaker attractive forces. For example, viscosity of benzene (C2H6) is 0-65 X 10-3 kg m-1 s-l
while that of ethyl alcohol (C2H5OH) is 1.20 x l0-3 kgm-1 s-1. This means that molecules in alcohol have
stronger intermolecular forces of attraction Compared to benzene molecules. These are hydrogen bonding
as well as dipolar forces.
It is our common experience that all liquids or fluids do not flow with the same speed. The
liquids like water, alcohol, kerosene oil etc. flow rapidly while others like honey, glycerol, and
castor oil etc. flow very slowly. This clearly shows that every liquid has a certain internal
resistance to the flow called viscosity.
Figure 5.29. Relative flow of different layers of a liquid
The internal resistance to flow is due to intermolecular forces of attraction present in different
liquids. If these are strong, the liquid is more viscous and in case these are weak, the viscosity of
the liquid is comparatively less.
We have seen that the viscosity arises due to internal friction or resistance between the
layers of a liquid as they pass over each other. When a liquid is flowing steadily over a fixed
horizontal surface, the layer of the liquid in immediate contact with the surface is stationary.
With the increase in distance from the fixed surface, the velocity of the layers increases. This
type of flow in which there is regular gradation of velocity in passing from one layer to the next
layer is called laminated flow. In case we select a particular layer, then the layer present
immediately below tries to retard or slow down its velocity while the one immediately above it
tends to accelerate the same. The force which is needed to maintain the flow in three different
layers of the liquid depends upon two factors, i.e.
1) Area or surface in contact (A)
2) Velocity gradient (du/dx)
If the velocity of the layer at a distance dz is changed by a value du, then the velocity gradient is
given by the amount du/dz.
Some force is needed to maintain the flow of layers.
Force (f) α (A) x (du/dx) = nA du/dx.
Viscosity
The different layers of the fluid in motion are found to move with progressively changing speeds.
For example, the speed of the top layers of water in the river is the highest and that of the bottom
layer is the lowest. That is, there is a velocity gradient along the depth of the river.
υ
c
u
D
dx
A
u-d u
P
B
Q
If we consider a particular layer of the flowing fluid, the layers above it tend to increase its
speed, but that immediately below tends to decrease its speed. This leads to internal friction
between the layers and a backward drag is produced to the motion of each layer of the fluid,
which is called viscosity. Thus, viscosity is the property of fluids by virtue of which a backward
drag or opposing force comes into play, whenever there is a relative motion between the different
layers of the fluid.
Co-efficient of viscosity
Suppose the layer AB is separated from the layer CD by a distance
dx.
Fig. 7.3.1. Then it is
found that the (backward) dragging force 'F exerted by the layer AB on those above it is
directly proportional to the area
difference
'dv'
'A'
(i)
of the layers, 07) directly proportional to the velocity
between the two layers under consideration,
(iii)
inversely proportional to the
distance 'dx' of separation of the two layers. Mathematically. we
Fα A
dv
dv
orF = −nA
dx
dx
Here n is the constant of the proportionality and called the co-efficient of viscosity of the
medium. The negative sign shows that the viscous force is directed opposite to the velocity of the
layers. Here dv /dx is called the velocity gradient.
If A=1,dv/dx=1 then F=n.
Hence, the co-efficient of viscosity is numerically equal to the viscous drag between two
layers each of unit area and having unit velocity gradient between them.
The layers of fluid in contact with the falling body move faster than those away from it, so
the groups drag comes into play. This is illustrated in $e fig- 7.3.2 by drawing arrows of
decreasing length as we go away from the falling body. Sir forge Gabriel Stokes, an English
physicist was first to carry out detailed investigation of the phenomenon. He found that the
viscous drag is given by
F = 6πηυ
This is called Stake’s law or Stake’s formula
In this study we study the effect of polar and non-polar solvent at different temperature on
viscosity of aliphatic and aromatic ketones.
These polar and non-polar solvent Liquid mixtures with Aliphatic and Aromatic ketones causes
different type of Intermolecular Interaction which result of change in viscosity of pure
compounds of Aliphatic and Aromatic ketones is useful for manufacturing of product to
detecting pour ability and pump ability.
In general, any atom consists of positively charged centrally situated nucleus and negatively
charged electronic charge cloud at some distance from the nucleus. An atom is always
electrically neutral as positive and negative charges are always equal. When a molecule is
formed by the interaction between two or more atoms, then there is a centre of positive charge
due to nuclei of reaction atoms and also a centre of negative charges due to electronic charge
clouds of the atoms. If the centers of positive and negative charges coincide at one point then the
molecule is said to be non-polar. In case of polar molecules, the centers of positive and negative
charges do not coincide. They are away from one another by a distance say 1 cm. Non-polar
molecules posses zero dipole moment while polar molecules posses non zero dipole moment. If
q esu is the electronic charge and 1 cm is the distance of separation of charges then the dipole
moment u is defined as the product of charge and distance of separation of charges. Thus,
u = q x 1 esu cm.
Dipole moment is measured in the unit of Debye unit and 1 Debye unit = 1D =10-18 esu cm.
A solvent having partial positive and negative charges separated by distance having two poles
i.e. dipole known as polar solvent.
The extent of polar character depend upon electronegetivety difference of
combining atoms greater is electronegetivety difference greater is polar character of solvent. The
polarity of solvents can be conveniently measured in terms of dipole moment.
A solvent of pure covalent bond having no any charges separation between atoms of molecules
considered as Non-polar solvent them having zero dipole moment. There are three main types of
intermolecular interactions are possible.
Terminal velocity:As the velocity of the falling body increases, the viscous drag on it also increases. A stage
comes, men the viscous drag is equal to the weight of tlie body, so the net downward force on the
body r&.ices to zero. After this stage, the body falls mm with a constant velocity, called the
terminal viocity. Thus, the terminal velocity of a body is tiff maximum velocity of fall in given
fluid, .parently, the terminal velocity, will have different vMues for different fluids.
Suppose, a spherical body of radius r and sixty p, has acquired the terminal velocity, say). Then
weight of the body
4
W = Mg = π r 3 ρ g
3
Viscous drag F = 6πη rυ1 , For motion with terminal velocity, we have f = W , therefore
or υt =
2r 2 ρ g
9 η
That is, the terminal velocity varies directly as the square of the radius of the spherical body,
directly as the density of the material of the body and directly as the acceleration due to gravity
and inversely as the co-efficient of the viscosity of the fluid.
Here, we have not taken into account the upward thrust due to buoyancy, which is equal to the
weight of the fluid displaced. If cr be the density of the fluid, then upward thrust is given by
Discussion:-
If ρ > σ , then υt is +VE and the spherical body falls down with a terminal
velocity. ρ = σ , the body floats (neither rises nor falls) and if ρ < σ , the body may
rise with a terminal velocity. The rising of the air bubbles in water or that of
hydrogen or helium filled balloons is due to this reason
Applications:The knowledge of terminal velocity helps in (i) determination of viscosity of the fluid and (ii)
streamlining of the vehicles. Also, Millikan was able to determine the charge on electron using
the knowledge of terminal velocity.
Streamlined and Turbulent Flow:The flow of a liquid is said to be streamlined, if each particle of the fluid passing through a given point
travels along the same path with the same velocity as the proceeding particle passing through that point
does.
The flow of a fluid is said to be turbulent (the velocity of the particles passing through a point changes
in some disorderly manner
The path of a particle, in a streamlined flow is called streamline.
The streamlined flow is also called lamellar or laminar flow. Because, the fluid having
streamlined flow can be divided into different layers or laminate adjacent to each other. For
example, the steady flow of viscous liquid in a channel is streamlined or lamellar and the
velocity profile is as shown in fig. 7.3.3. However, for a non viscous fluid the velocity profile is
different as shown in fig. 7.3.4. Thus, the streamlined flow of a viscous fluid has a velocity
gradient between different layers, but that of non viscous fluid has all layers moving with the
same velocity.
u1
---------
u1=u1
---------
u1
---------
---------
---------
---------
u2
-------------------------
-------------------------
u2
---------
---------
---------
-----------
Critical velocity and Reynolds number:Osborne Reynolds proved experimentally in 1883, that there is a certain velocity of flow at which the
streamlined flows turns turbulent. This is called critical velocity. We may denote it by vc . Reynolds
also obtained the expression for critical velocity as follows.
υt =
Rη
ρd
………………(i)
Where η is the co-efficient of viscosity of the fluid, ρ is the density of the fluid and d is the
diameter of the tube in which the fluid is made to flow. R is called Reynolds number. It is found
that for streamlined flow R lies between 0 to 2000. And that the flow of the fluids becomes
turbulent when R is more than 3000. For R between 2000 and 3000 the nature of flow is unstable
and cannot be clearly predicted.
From the equation (i), we can find the critical velocity for a fluid. If the fluid is highly
viscous but of low density and is flowing in a tube of small diameter, then vc is large. That is, the
flow of such a fluid can be streamlined even at large velocities. However, for fluids of low
viscosity and high density, the flow may turn turbulent even at a low velocity.
Equation of Continuity
The equation of continuity expresses the law a fluid following in tube of varying areas of cross
section.
Let a1 , υ 1 and ρ 1 respectively be the area of the cross section of the tube, velocity of flow of the
fluid particles and density of the fluid at point A. Similarly, a2 , υ 2 and ρ 2 be the area of cross
section, velocity of the fluid particles and density of the fluid at point B.
Since there is no sink or source of fluid in between points A and B; therefore, mass flux at point
A = mass flux at point B.
i.e
a1 υ 1 ρ 1 = a2 υ 2 ρ 2
Since liquid is incompressible, i.e. ρ 1 = ρ 2 = ρ (constant)
Therefore, equation (i) can be written as a1 υ 1 = a2 υ 2
In general, a υ = constant. That’s called equation of continuity and states that as the area of cross
section of the tube of flow becomes larger, the liquid (fluid) speed becomes smaller and viceversa.
Bernoulli's Equation:Bernoulli's equation is a fundamental relation in fluid mechanics. It states that for an ideal
incompressible and non- viscous fluid having streamlined flow, the sum of pressure energy, kinetic' energy
and potential energy per unit mass is always constant.
i.e.
1
+ υ 2 + gh = constant …..(i)
ρ 2
P
Every tern of this equation has dimensions of length and is called a head. p is called pressure
ρg
2
land v the velocity head and h is the gravitational head. That is for an ideal incompressible
2g
and non viscous fluid having streamlined.
Flow, the sum of the pressure head, gravitational head and velocity head is constant. This is
another statement of the Bernoulli’s theorem.
For horizontal flow, h is constant, so equation (i) reduces to
1
constant
+ υ2 =
ρ 2
g
p
Form this expression it is clear that pressure is large when the velocity of the flow of fluid is low
and vice-versa.
Nernst Distribution Law:1. Solutions
of
Liquids
in Liquids.
A liquid may or may not be soluble in another liquid. Depending upon relative solubility of
a liquid in another, the following three cases are possible :
( i ) Completely miscible where the two liquids are soluble in each other in all proportions, e.g.,
benzene in toluene, alcohol in water, chloroform in acetone.
(ii)
Partially miscible, in which case a liquid is soluble in another to some extent only. The
resulting mixture consists of two layers each being a solution of one in the other. Examples of
this type include glycerol and water, phenol and water, nicotine and water.
(iii) Immiscible, in this case the two liquids do not dissolve each other and remain separated in
the mixture, e.g., carbon tetrachloride and water, benzene and alcohol, carbon disulphide and
water, etc.
Miscible Liquids:Based on the forces of attraction between the molecules of liquids A and B, solutions of miscible
liquids may be of the following types :
Ideal solutions:This type is characterized by complete uniformity of cohesive forces. If there are two
components A and if, the forces between A and A, B and B, and A and B are all equal. When
this is true,
(a) Total volume of the solution =Vol. of A+ Vol. of B.
( b ) No heat is evolved or absorbed on mixing the component,
For example, when a liter each of benzene and toluene are mixed together at room temperature,
the volume of the resulting solution is two liters because they form an ideal solution. In this case
this is no heat evolved or absorbed. On the other hand, on mixing 100 c.c. of sulphuric acid with
100 c.c. of water, the quantity of hint generated is so large that an ordinary beaker may give way.
The volume of the mixture will also be nearly 180 c.c. This is because they form a non-ideal
solution.
Viscosity and Constitution:The connection between viscosity of a liquid and its chemical constitution is
not very marked, though a few relationships have been noticed. For example, in
homologous series, the increase in viscosity per CH 2 group is roughly constant.
An interesting relationship I between viscosity and molar volume was discovered
by Duns tern in 1909 and has been found to be useful. It may be expressed as follows:
d
×η ×106 = 40 to 60
M
Wherein d is the density, M the molecular weight and the coefficient of viscosity
of the liquid. The relationship is true only for non-associated (normal) liquids. For
associated liquids this number is considerably greater than 60. This relation is very
useful in deciding whether a given liquid is associated or not. The values of (d/M) η
X10 6 for a few substances and the inference we can draw in each case, are given in Table
5'4.
Molecular Viscosity, bioce M j d represents molar volume, (M/d)f will repres-nt the
surface area of one mole of the liquid or molar surface. T h e product (>f molar surface
and viscosity is called Molecular viscosity, i.e.,
Molecular viscosity=Mole;ular surface X viscosity
= (M/d)2/3 X η
Thorpe and Rodger (1894,: found the molecular viscosity to be an additive and
constitutive property and prepared a table of values of molecular viscosity contributions
by different atoms as given below :
Atom
H
C
O(-OH) O(-CO)
S
Molecular viscosity
80
-98
I96
155
248
results, however, have: not been very satisfactory.
Rheochor,
Newton Friend suggested that another constant could be obtained by
multiplying the molar volume of the liquid by the eighth rcot of its viscosity at the same
temperature.
He named this constant the rheochor and represented it by R,
Mathematically,
R = (M/d)η 1/8
Physically rheochor of a liquid may be regarded as its molar volume at a temperature
when its viscosity is unity, it is an additive and constitutive pioperty but no>t a very good
one which could solve any constitutional problems.
Dipole-dipole interaction:
These Interactions observed between two polar molecules having permanent dipole moment.
When two polar molecules approach each other in such way that oppositely charged end come
closer to one another to form dipole-dipole Interaction. The dipole-dipole Interaction strength
based upon dipole moment of Interacting molecules. During such type of Interaction electrostatic
force of attraction developed between Liquid mixtures which results change in viscosity of
binary liquid mixture. As higher the dipole moment stronger is the intermolecular interaction
cause increase in viscosity of liquid mixtures.
δ- A--------B δ+
……………
Polar molecule
δ -A--------------B δ+
Polar molecule
Dipole-induced dipole interaction:This type of interaction observed between a polar molecule which having
permanent dipole moment and non-polar molecule of zero dipole moment. When polar and non
polar molecules approach each other the polar molecules induce dipole in the non-polar
molecule.
The electronic charge cloud is the distorted and temporary separation of charges takes place and
force of attraction is developed between charge separated polar and charge induced non polar
molecules as shown below.
δ- A--------B δ+
……………
Polar molecule
C
Non-Polar molecule
with induced dipole
Dispersion forces or London forces:This type of interaction between atoms as well as non-polar molecules is through
dispersion forces which depend on polarity of the atom or molecule. Polarity is depending upon
the arrangement of electrons in the atom or the molecule can be disturbed. In case of bigger
atoms or molecules, the number of electrons revolving in the orbits is large and the electron
charge cloud is more diffused i.e. spread over longer volume. Therefore, the electrons are held
loosely by the nucleus.
Consider, an atom or a non-polar molecule with nucleus or nuclei at the centre
and electrons are revolving around it, suppose that at a particular instant the position of nucleus
and electrons at this instant the centers of positive and negative charges do not coincide. Hence
at that incant the atom or molecule has a nonzero dipole moment. This nonzero dipole moment
of non-polar molecule is called instantaneous dipole moment, as this dipole moment is valid for
that instant which is a very small time interval. At the next instant the position of dipole charges
and so on.
However, it is true that the atom has zero dipole moments as all the instantaneous
dipole moments cancel each other but in a collection of atoms the instantaneous dipole may
induce in the atoms or molecules in the vicinity and then interact with these induced dipoles.
This interaction produces dispersion forces. Dispersion forces are the force that originates
instantaneous dipoles and induced in atoms or molecules generally at very low temperature; the
kinetic energy of atoms or non-polar molecules is reduced to great extent. In addition at higher
pressures the interatomic or intermolecular distance are negligibly small, interatomic or
intermolecular dispersion forces are strong which hold the atoms or molecules together.
In1930, German physicist Friz London proposed the idea of instantaneous dipole and the
presence of dispersion forces. London proved that the extent of attractive interaction is directly
proportional to the polarity of the atom or molecule, dispersion forces are very weak and also
called London forces. The strength of London forces increase with shape, size, molar mass and
the number of electrons present in an atom or molecule. Dispersion forces are present in all
molecules in addition to other forces. In non-polar molecules other forces are absent and only
dispersion forces exist.
A
……………
Non-Polar molecule
B
Non-Polar molecule
Hydrogen Bond:When hydrogen is bonded to another atom having stronger electronegetivety then
the stronger electronegetivety atom attract shared pair electron towards itself and become highly
electronegative where as hydrogen atom becomes highly electropositive. Due to movement of
electrons towards other atom, hydrogen acquires slightly positive charge while other atom
acquires slightly negative charge. It results into the formation of a polar molecule having a
electrostatic force of attraction.
The strength of hydrogen bonding changes with physical state of compound. It is maximum in
the solid state and decreases liquid to gaseous state. Thus, the hydrogen bonds affects on
structure and properties of the compounds.
There are two types of hydrogen bonds, Inter molecular hydrogen bond And Interamolecular,
hydrogen bonds.
Inter molecular hydrogen bond:It is formed between two different molecules. For example hydrogen bonding in
HF, alcohols, ammonia, water etc.
In alcohols, oxygen is mote electronegative than hydrogen atom as well as alkyl group produces
polarity in -O-H bond. Thus in alcohol molecule oxygen atom is stronger electronegetivety
carries partial negative charge and hydrogen atom is highly electropositive carries partial positive
charge. There exists intermolecular hydrogen bond amongst molecules of alcohol.
Intramolecular Hydrogen bonds:It is formed between highly electropositive hydrogen atoms with other stronger electronegative
atoms present within the same molecule.
Intramolecular hydrogen bonding increases the melting point, boiling point, solubility, viscosity
and surface tension while intramolecular hydrogen bonding has opposite effects. This is because
the two ortho-substitued groups undergo intermolecular hydrogen bonding which prevents their
association their association with other molecules.
d+
H
dO
R
d+
H
dO
R
d+
H
dO
R
d+
H
dO
R
To study of the nature of intermolecular interaction among the binary mixture of aliphatic and
aromatic ketones with polar and non-polar solvents are receiving attention in chemistry because
of their importance in industrial processes.
Knowledge of viscosity is important in engineering designing, new Technology process. Product
dimension, petroleum industries, oil industries, metallurgical manufacturing process such as
casting and rolling etc Calculating forces and momentum on aircraft, predicting weather pattern,
in weapon detonation, optical fiber, soap industries, plastic industries etc.
The measurement of viscosity is of considerable importance in both industrial production and
fundamental science. Viscosity is the quantity that determines the force to be over come when,
fluids are used in pipelines or bearing and it controls the flow of liquid in such processes. In
other application the measurement of viscosity affords a convenient means of checking the
constancy of product. Viscosity measurement has also proved to be a valuable tool- for physical
chemistry science. The Viscosity coefficients are profoundly depend on intermolecular attraction
and size, shape of the liquid molecules.5-8
1.3 Importance and Scope
To study of physical properties like viscosities, densities of aliphatic and aromatic ketones and
their binary mixture with polar and non-polar solvents are receiving attention in chemistry
because of their importance in industrial processes. These physical properties involve challenges
of interpreting the excess quantities as a means of understanding the nature of intermolecular
interaction among the binary mixture. From the study physical properties ideal behavior, the
nature of interaction between molecules can found out.
Densities of liquid mixture and related volumetric properties such as molar excess
volume are required for theoretical calculation as well as applications. The sign and value of
molar excess volume gives strength of interaction in binary mixture of ketones with polar and
non-polar solvents. Larger the positive value of molar excess volume indicates weak interaction
and dissociation between binary mixtures. Whereas larger negative value of molar excess
volume indicates strong interaction and intermolecular association between binary mixtures are
believed to be present. Viscosities of liquid mixtures are useful for the calculations in
engineering where fluid flow, mass transport and heat transport are important factors. Viscosity
of binary mixture gives valuable formation about nature of liquid-liquid molecular interaction
and forces operating within and between molecules. Now a day’s computer simulation method of
dynamics gives information of molecular theory of transfer properties in liquids and get
knowledge of molecular motion and interaction patterns in system showing dispersion and
specific interaction in liquid-liquid mixture of both non-hydrogen bonding and hydrogen
bonding solvent. 9-16
In the present work, liquid mixtures of ketone with polar and non polar solvents
and thermodynamic properties like densities and viscosities of will be measured over complete
range of composition at three different temperatures. From these values of densities and
viscosities, molar excess volume, deviation in viscosity will be calculated.
The observed deviation in viscosity may be showing different type of specific
interactions like hydrogen bond and dipole-dipole and to found out inter molecular interactions
nature between two liquids of binary liquid mixtures interaction parameters like dispersion forces
study is useful.
The need for physical properties of aliphatic and aromatic ketones is ever
increasing to make industry processes more economical. The main variables density, viscosity
and conductivity that are evaluate the aliphatic and aromatic ketones. Density, viscosity and
conductivity are function of temperature. It extremely to predicting these physical properties it is
difficult to develop reliable models because of the complex chemical nature of ketones. Ketones
density and viscosity decrease with increase in temperature. Whereas with increases temperature
ketones conductivity increases exponentially which causes a higher rate of power consumption.
A good survey of physical proportion of ketones is a critical evaluation, and correlation would
help designer engineers, scientists and technologists in their area of interest. In terms of refining
and many other industries.15-20 Ketones are always an increasingly more importance.
The Cohesion force was the molecules- molecules attractive forces. When the
temperature is increased the molecular distance increased, and cohesion force of attraction
decrease. Thus viscosity depends upon its molecular momentum transfer rate and forces of
cohesion. Transfer of molecular momentum is due to random movements of liquid molecules
between different layers of liquids, which cause friction between adjacent layers. Liquids
molecules are more closely spaced as compare to gases molecules, having strong cohesion force
and higher viscosity as temperature decreases cohesion increase, viscosity also increases.20-25
In general, the viscosity decreases with increase in temp. As temp increase,
activation energy increases. Liquid can flow more easily at high temp hence viscosity decease.
The best known equation for representing the viscosity temp relation is due to Andrade Guzman
mathematical equation as shown below.
η = A E a/R T ............(1 ) o r  η= A "E x p B '/t 
Where η is viscosity, T is temp in Kelvin
A & Ea are constant for given liquid
R is molar gas constant.
Ea is Activation energy flow. By taking logarithms on both sides, of equation (1) we get
Ln η = E a / R x 1 / T + A ............ ( i i )
Comparing equation (ii) with straight line equation
Y = mx +c.
However, a plot of viscosity η V/s.1/T was liner suggest by simple viscosity
models.
From this point of view, during this work there will be focus of our attention on
effect of various substituent electrons donating or accepting on the viscosities of ketones again.
There will be an interesting point to see co-relation between change in the thermodynamic
parameter with viscosities of ketones at different temp from their studies we may also be able to
determine the activation energy shear stress, density and factors affecting. The viscosities of
ketones are, their studies have direct relevance to the present day problem and needs of industry,
pharmaceuticals, medicine and fundamental science researchers.
25-33
During this work there will be focus of to see co-relation between change in the
thermodynamic parameter with viscosity of ketones and binary mixture at different temperature.
From this study we may also be able to determine the activation energy shear stress, change of
density. Temperature dependence can be more complex because the density of ketone may also
change. Thus the viscosity is complicated physical property depending upon a temperature and
number of variables in addition to which are not easily controlled. The main variable of aliphatic
and aromatic ketones as density, viscosity and conductivity is function of temperature, an
increase in temperature decrease in density and viscosity but conductivity increases
exponentially with temperature which cause a higher rate of power consumption, a good survey
of physical proportion of ketones is a critical evaluation and correlation would help designer
engineers, scientists and technologists in their area of interest.
The need for physical properties of aliphatic and aromatic ketones to make industry
processes more economical in terms of refining and many other industry ketones are always an
increasingly more importance.
1.4 Significance of the study
Physico-chemical study of liquid mixture of ketones with polar & non-polar
solvent are investigate the molecular interaction. A substance exists in liquid state and not
gaseous state because, There are intermolecular forces of attraction are greater in liquid state as
compare to gaseous state attractive force between molecules and atoms are referred to as Vander
Waals forces and may be of three type.1.Dipole-dipole interaction. 2. Dipole-induced dipole
interaction. 3. Induced dipole- induced dipole interactions.
In this present work, viscosity of aliphatic and aromatic ketones and their binary
mixtures with few selected polar & non-polar solvents will be measured at three different
temperatures, to collecting a viscosity data of ketones binary mixtures given important in
manufacturers an product. Knowledge of viscosity data of ketones is useful in predicting pump
ability, pour ability, performance in a dipping and coating operation which it may be handled,
processed and used. The measurement of viscosity of ketone the most important and convenient
way of detecting changes in density and molecular weight, The interrelation between theology
and other product dimensions may also Viscosity measurements are also useful in the following
process of chemical reactions. Such measurements are 1.Quality check during production, 2.To
monitor or control a process, 3. The study of chemical, mechanical and thermal treatments the
effect of additives, ultimately the viscosity measurement ketones are much useful behavioral and
predictive information to take guidelines in formulation, processing and product development.
We have chosen those ketones which have wide range of applications in various
industries such as perfumery industry, insecticides industry, agrochemical industry,
pharmaceutical industry, manufacturing of resins, fragrance industry, cosmetics industry,
refinery industry, cement kilns industry, lumber industry wood mills industry, paper mills
industry and also these ketones are being utilized to the large extent as flavoring agents in food
materials, antimicrobial, as precursors to many other important chemicals, as preservatives, as
corrosion inhibitor and these ketones are also used as solvents or reagent in many chemicals
reactions.
Here are some important applications of few ketones as mentioned below.
Aliphatic ketones propan-2-one and 2- butanone species have dipole-dipole
interactions because lack of hydroxyl group aliphatic ketones do not form hydrogen bond with
each other hence intermolecular forces are weaker than alcohols. These ketones are good
solvents for resins, polymers waxes dyes stuff and cellulosic’s. So they are important in polymer
processing industries as plasticizers and manufacturing wide variety of coating and plastics.
Aromatic ketones acetophenone and propiophenone involve dipole-dipole interaction. Because
these are aprotic solvents hence involve weak intermolecular interaction. Acetophenone is used
as precursors to resins raw material to synthesis of pharmaceuticals like dextropropoxylphene
and phenylpropanolamine. Propiophenone is useful in intermediate to prepare nervous system
drug like Bupropion and Paraoxypropione.
Alcohols methanol, ethanol are polar character. The dipole-dipole type Vander
Waals forces is present. In addition to dipole-dipole forces alcohols are hydrogen bonded and
thus involve strong intermolecular interactions. Physico- chemical properties of aliphatic
alcohols varies with variation in increasing chain length of alkyl group. Alcohols are most useful
solvent used to study the hydrophobic effects in pharmaceutical industries.
The aromatic hydrocarbon benzene and toluene are non-polar compounds with no
measurable dipole moments and therefore the only Vander Waals forces are to be considered are
the induced dipole-induced dipole type. Thus they involve weak intermolecular interactions.
They find application in petroleum industry.²⁷⁻³⁶
The thermo physical property that is viscosity of a fluid is valuable significance and one great
importance in many scientific and industrial areas. During the process of transport ting fluids or
pumping fluid, For example, it is known to pumping fluid in the petroleum industry through a
pipeline into many processing units. Viscosity of the fluid affects the flow rate of a pump and
hence it is to know the viscosity of the fluid being transferred, for that purpose the viscosity to be
known precisely. The viscosity is also controlled the power consumption of the pump that means
the more viscous the liquid, the more power the pump needs. It determines extrusion, printing
and spraying process the flow rate have important applications.
1.5 OBJECTIVE
1.
Viscosities measurement of selected Ketones at three different temperatures and to show
correlation between extents of viscosities changed with an increase or decrease of
temperatures by 50C.
2.
To obtain information regarding factors affection on viscosity. Like temp, pressure,
molecular weight and density.
3.
Determination of specific interaction, molar refraction, share rate, shear stress of ketones.
4.
Attention to the co-relation between viscosities and density with thermodynamic
parameters.
5.
To focus of our attention on effect of different substituent on the viscosities and density
of ketones.
1.6 HYPOTHESIS
This study is significant because it is applied aspect. A brief account on observed
fact concerning the effect of temperature, molar mass and density of liquids on viscosities and of
selected ketones and how these facts may be interpreted will be presented through his work. We
may also come to known the effect of various substituents on the viscosities of ketones. The
viscosity data correlated with thermodynamic parameter. This correlation will be observed
through the experimental facts.
The present study is to obtain information knowing about interactions between
highly polar liquid molecules with non-polar molecules and weakly polar liquids molecules by
objective understanding; The Viscosities of ketones will be useful through which other
characteristics of liquid may be observed. The significance of this work is the viscosity is the
fundamental property that can be used in conjunction with other properties to characterize pure
ketones.
The measurement of viscosities ketones can be functioned for the area of quality
control, where raw materials must be consistent. For this purpose, product consistency and
quality will be measured by flow behavior indirectly.
Many manufactures now for development, and process control programs regard
viscometers as main part of their research, Because of that viscosity measurements are, most
accurate and most easily able often the quickest way to analyze some of the most important
factors which affecting product quality and quantity. Viscosity value have numerous application
in UV Curable coating, inks, optical fibers, plastic industries, soap industries, petroleum
industries, oil industries and researchers in chemistry, biology and medicine field.