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Que.: Mahmud Of Ghazni: Why He Attacked 17 Times On India?
Que.: A trader who marks his good upto 50% and offered discount of 20% . What % profit the trade makes after offering the payment?
Then,
Required s.p = 125% of Rs 600 Answer (b)
Que.: How do bats search their prey?
Bats generate high-pitched ultrasonic waves which are then reflected from the obstacle or prey and return back to bat’s ear.
This phenomenon help bats to search out prey and fly in dark night.
Porpoises also use the same technique for navigation and location of food in the dark.
Que.: what is the full form of SSC?
Que.: What is the full form of CAPF?
Que.: What is the full form of RSSB and RSMSSB
Que.: how to get admission in delhi university?
Que.: what is DUET?
Que.: What is the last date of DU admission form submission?
Que.: what is the fee for DUET Registration?
Que.: Can IGNOU students apply for PG in DU?
Que.: IBPS का पूरा नाम क्या है?
Que.: what is the minimum qualification we should have to apply for banking jobs?
Que.: What is the last date for IBPS form submission?
Que.: What is the fee for IBPS online form?
Que.: What is the full form of RRB in banking?
Que.: What is PO in banking?
Que.: What is CRPF?
Que.: which organisation conducts NORCET?
Que.: What is the last date for NORCET 2020 application?
Que.: What is NORCET Exam?
Que.: What is the NORCET 2020 exam date?
Que.: What is CET?
Que.: How long the CET score will be valid for?
Que.: What is full form of SHSB?
Que.: What is selection processor for ASHA Workers?
Que.: What is Nobel Prize?
Que.: How many questions from general science included in competitive exams??
ie. SSC EXAM
1.General Awareness - GK + current affairs (20 questions) + general science (20 questions)
2. Mathematical ability (20 questions)
3. Language test (20 questions) any one languages Hindi or English.
4. General intelligence and reasoning (20 questions)
Que.: What is GPAT?
Que.: What is the application fee for GPAT?
Que.: What is the duration of GPAT exam?
Que.: What is the language mode of GPAT exam?
Que.: Who conducts the GPAT?
Que.: What is the minimum qualification for GPAT?
Que.: Who decides the syllabus for GPAT?
Que.: What is the mode of GPAT CBT or pen paper??
Que.: What is pharmacy act?
Que.: What is Drugs and Cosmetics Act 1940?.
Que.: what is a prime number?
Que.: what is a perfect number?
The factors of 6 are 1, 2, 3, and 6. And, 1+2+3 = 6.
Que.: Why Dalton's Atomic Theory Failed ?
Que.: which atomic model states about energy levels of an atom?
Que.: what is the full form of ISRO?
Que.: what is ICRB?
Que.: If ratio between a and b is 2 : 3 and ratio between b and c is 5 : 7, then find the a : b : c ?
\( {b \over c } = {5 \over 7 }\)
as b is the common quantity so, we will make its value common on both the ratios.
a : b = 2 : 3
b : c = 5 : 7
a : b = \( { 2 \times 5 \over 3 \times 5 } \)
b : c = \( { 5 \times 3 \over 7 \times 3 } \)
∴ a : b : c = 10 : 15 : 21 Answer
Que.: What are the Bence jones proteins and how to test for the bence jones proteins in urine?
Presence of BJPs in urine results multiple myeloma (plasma cell tumour).
When urine containing Bence jones proteins is heated in a test tube in temperature between 50 to 60 ℃ , a ppt formed which on heating at a temperature of 100℃ get disolves.
Que.: how to sign up on solotutes.com?
Que.: what is the Structure of Indian Constitution ?
Que.: Department of transport test is performed for which of the following
Ans... Aerosols
Que.: How to proceed for Packaging of Pharmaceuticals
Que.: Define sterilization
Que.: Discuss briefly various methods of sterilization
Que.: What is the application fee for medical officer post at Oil India?
For SC/ST/PwBD/Ex-Servicemen - NIL
Que.: Which is the longest part of alimentary canal?
Que.: questions on indus valley civilization
2.The bust of bearded man figure was found in which of the following archeological site?
3.The stone sculpture of male torso was found in which of the following archeological site?
4.Which of the following raw material was not used by the Indus Valley Civilization?
5.Which of the following artefact of the harappa civilization was mainly used for commercial purpose?
Answers:
1.Lost Wax Casting
2.Mohenjo-Daro
3.Harappa
4.Seal
5.Limestone
Que.: How many days Constitution of India was written?
Que.: What is the full form of APPSC?
Que.: What are the jobs in APPSC Recruitment 2021?
Que.: What is the Minimum Qualification for APPSC Recruitment 2021?
Que.: What is the Application and Exam Fee for APPSC Recruitment?
Que.: What is The Selection Process for APPSC Jobs?
Que.: When and Where to Apply for APPSC Recruitment 2021?
Que.: What is Swachha Sarvekshan?
Que.: Which team won the maximum IPL titles?
Que.: Who is the most run scorer in the IPL?
Que.: Who is the highest Wicket taker in the IPL?
Que.: Name the player who hitted the most sixes in IPL history?
Que.: Which player won most IPL titles?
Que.: Which team is maximum time runner up in the IPL?
Que.: what are vitamers?
Example -
1. Retinol, retinal and retinoic acid are vitamers of vitamin A.
2. Pyridoxine, pyridoxal and pyridoxamine are vitamers of vitamin B6.
Que.: Fat soluble vitamins are
Que.: Water soluble Vitamins are
Que.: Energy- releasing and hematopoietic Vitamins are
Que.: What is the Full form of UCO Bank ?
Que.: what is the last date for mp patwari ?
Que.: when will online applications start for MP patwari job?
Que.: What is the full form of MPPEB
Que.: Name the factors which affect spreading?
Factors Affecting Spreading:
1.If excess of spreading material is added, although initial spreading has occurred, saturation takes place and material may coalesce on the surface.
Thus when mutual saturation takes place, spreading coefficient is decreased or becomes negative. In case of organic liquid spread on water, the final spreading coefficient is always negative. Duplex films of this type are unsaturated and form monolayer with excess materials remaining as a less on the surface.
2.The types of molecular structure decide the spreading coefficient. An oil spread over water because it contain polar groups such as - COOH or - OH. Ethyl
alcohol and propionic acid have high value of S. As
number of polar groups increase, there is more spreading on water. As polar/ non-polar character increases, spreading coefficient increases. As the carbon chain of an acid increases, the ratio of polar/non-polar character decreases and spreading coefficient on water decreases.
3. If cohesive force between molecules is less than adhesive force between sublayer and spreading liquid, the liquid spreads e.g., benzene spreads on water not because it is polar but because the cohesive force between its molecules are much weaker than the adhesion for water.
Spreading coefficient has important application in pharmacy e.g., in order for lotion with a mineral oil base to spread freely and evenly on the skin its polarity and hence its spreading coefficient should be increased by addition of surfactant.
Que.: Name the factors which affect spreading?
1.If excess of spreading material is added, although initial spreading has occurred, saturation takes place and material may coalesce on the surface.
Thus when mutual saturation takes place, spreading coefficient is decreased or becomes negative. In case of organic liquid spread on water, the final spreading coefficient is always negative. Duplex films of this type are unsaturated and form monolayer with excess materials remaining as a less on the surface.
2.The types of molecular structure decide the spreading coefficient. An oil spread over water because it contain polar groups such as - COOH or - OH. Ethyl
alcohol and propionic acid have high value of S. As
number of polar groups increase, there is more spreading on water. As polar/ non-polar character increases, spreading coefficient increases. As the carbon chain of an acid increases, the ratio of polar/non-polar character decreases and spreading coefficient on water decreases.
3. If cohesive force between molecules is less than adhesive force between sublayer and spreading liquid, the liquid spreads e.g., benzene spreads on water not because it is polar but because the cohesive force between its molecules are much weaker than the adhesion for water.
Spreading coefficient has important application in pharmacy e.g., in order for lotion with a mineral oil base to spread freely and evenly on the skin its polarity and hence its spreading coefficient should be increased by addition of surfactan
Que.: What is adsorption? What are the factors which affect adsorption?
Adsorption: When a solid surface is brought in contact with a gas or liquid, molecules from the gas or liquid starts to collect at the surface of the solid. This phenomenon of a collection of gas or liquid molecules on the surface of the solid is known as adsorption. A substance which accumulates on the solid surface as known as adsorbate and the solid surface on which it occurs is known as an adsorbent.
Factors affecting adsorption:
Factors affecting adsorption are given by-
1. Nature of adsorbent
2. Surface area
3. Nature of the gas
4. Exothermie nature
5. Pressure.
1. Nature of Adsorbent:
In general, if a gas is more liquefiable it will be more easily absorbed. For example, gases like NH4, , HCI, Cl2, CO2, which can be liquefied easily are more readily adsorbed on the solids surface rather than permanent gases like 02, H2 etc.
2. Surface Area:
When we increase the surface area of the adsorbent there is an increase in the adsorption of gases. This is because when we increase the surface area there is more number of adsorbing sites. So finely divided solids and some porous substances are good adsorbents.
3. Nature of the gas:
In general, if a gas is more liquefiable it will be more easily absorbed. For example, gases like NH4, HCI, Cl2, CO2, which can be liquefied easily are more readily adsorbed on the solids surface rather than permanent Bases like O2, H2 etc.
4. Exothermic nature:
The heat of adsorption can be defined as he energy liberated when 1 g mol of a gas is liberated on a solid surface.
Que.: Write a short note on surface free energy.
Surface Free Energy:
To move a molecule from the inner layers to the surface work needs to be done against the force of surface tension. Thus, the molecule near the surface of liquid have more potential energy as compared to the bulk of the liquid.
As the surface of the liquid increases more will be the energy since this energy is proportional to the size of the free surface energy.
Each molecule of a liquid has tendency to move inside the liquid from the surface thus minimizing the surface free energy. Thus a Liquid droplet tend to assume a spherical shape since sphere has smallest surface area per unit volume.
Que.: Describe about the Drop Weight Method (Stalagmometer).
Drop Weight Method (Stalagmo-meter):
- The stalagmometer consist of a glass bulb about 10 cm in capacity with narrow capillary tube joined above and below.
- The straight parts of the tube above and below are graduated. The liquid whose surface tension is to be determined is sucked into the tube to fill it above the upper fixed mark.
- By adjusting pressure of pinchcock the liquid is allowed to flow out slowly in such a manner that each drop is fully formed to a maximum size at the tip before breaking off.
- A drop will cling to the end of the tube as long as its mass does not exceed surface tension force.
- In this way the number of drops flowing out as liquid runs down between mark A and B is determined. Usually, volume of liquid (v) between marks A and B would not confined to an integral number of drops of liquid but it would be a whole number plus a fraction of a drop.
This fraction is calculated by noting a number of divisions remaining filled above or below B as last drop flow out and by separately determining the number of divisions equivalent to one drop of liquid.The principle of this method consists of equating weight (w) of fully developed one drop just before it breaks off from the tip with force of surface tension (i.e., 2pir) where 'r' is the radius of exit tip and y is surface tension of liquid.
Que.: Write a note on surfactant (Surface active agent).
Surfactant:
- Molecules and ions that are adsorbed at the interface are termed as surfactants, surface active agent or amphiphiles. Thus the molecules or ions have a certain affinity for both polar and non-polar solvent. These compounds have structure that contain 2 separate regions, a hydrophilic region which confers on the compound solubility in water and a hydrophobic or lipophilic region in which renders material soluble in hydrocarbon.
- The lipophilic region is expelled from water phases but hydrophilic region prevents the surface active agent to be completely expelled from water phase.
Because of this dual structure it is energetically favourable for these materials, when dissolved, to adsorb at the interface orienting themselves in such a manner that the regions are with appropriate solvents.
- The addition of a surfactant to water results in their orientation at the surface which also subsequently causes a decrease in the surface tension of water. Hence they are also called as surface active agents.
Thus all surfactants are characterized by having 2 regions in their molecular structure:
- A lyophobic (hydrophobic/lipophilic)region such as hydrocarbon chain with has no affinity for aqueous solvent.
(ii) A lyophilic (hydrophilic) region that has affinity for water.
Que.: Classify surface active agents.
Classification of surface active agents: Surface active agents are classified in the following ways:
On the basis of the chemical nature:
Thus, according to the nature of the hydrophilic groups they are of four types:
Anionic: Where hydrophilic groups carry negative charge on ionization.
Cationic: Where hydrophilic groups carry positive change on ionization.
Non-ionic: Which do not tend to ionize.
Ampholytic: Where positive and negative charge both are present within the surfactant.
Que.: Give the name of methods for determining surface and interfacial tension.
- Capillary rise method
- DuNOUY tensiometer method
(iii) Drop weight method(iv) Drop count method
(v) Wilhelmy plate method.
Que.: Write a short note on Absorption.
Absorption
- Adsorption is the condition in which the atoms, ions or molecules are absorbed by another substance particularly in the solid liquid material.
- It is a bulk phenomenon.
- Absorption reaction occurs at a uniform reaction rate.
- Absorption is an endothermic process.
- There is no change in concentration.
- The temperature does not effect the adsorption process.
- The adsorption process is applied on cold storage, ice production and in turbine inlet cooling.
Que.: Write a short note on Physiosorption.
- It is also known as physical adsorption.
- The reason behind physiosorption isVan der Waals forces.
- Physical adsorption is reversible in nature.
- It is not at all specific in nature.
- Physisorption has a very low adsorption enthalpy of nearly about 20 to 40 kJ/mol.
- It takes place favourably in low temperatures.
- As the temperature increases the amount of physisorption taking place decreases.
- Since physiosorption has weak Van der Waal forces, it results in a multimole-cular layer.
- Physical adsorption has less activation energy.
Que.: Write a short note on Physiosorption.
Que.: Write a short note on solid/liquid interface.
Adsorption onto the solid surface of molecules dissolved in solution may occur if solute molecules and solid surface have chemical groups capable of interacting. In addition, non-specific or general adsorption may also occur if solute is surface active.
Adsorption from solution is usually more complex than from a gas because of solvent and other components present in the system. Adsorption from solutions may be measured by separation of solid and solution and estimating the amount of adsorbate adhering to solid or the loss in concentration of adsorbate from solution phase.
The solvent can complete for the site of adsorption, it would also determine. escaping tendency of solute i.e., more polar the molecules, less is the adsorption.
Que.: Discuss in detail about the solid/ Gas interface.
The degree of adsorption of gas by solid depends on the chemical nature of
adsorbent (material used to adsorb the gas) and the adsorbate (substance being adsorbed), the surface area of the adsorbent, the temperature and partial pressure of the gas.
This type of adsorption called as physical adsorption is associated with Van der Waals forces. It is reversible and removal of adsorbate from adsorbent is called as desorption.
A physically adsorbed gas may be desorbed from a solid by increasing temperature and pressure. Chemiosorption is a process where adsorbate is attached to adsorbent by primary chemical bonds.
The relationship between the amount of gas physically adsorbed on a solid and equilibrium pressure or concentration at constant temperature yields an adsorption isotherm.
An isotherm is defined as a plot.at constant temperature. The number of moles, gm or ml 'x of gas adsorbed on 'm' grams of adsorbent at STP (standard temperature and pressure) is plotted on the vertical axis against the equilibrium pressure of the gas in mm of Hg on horizontal axis.
Adsorption data can be measured by an apparatus called as 'Quantasorb'. It essentially consists of a balance contained within a vacuum system. The solid previously degassed is placed on the pan and known amount of gas at a known pressure is allowed to enter.
The increase in weight at the corresponding equilibrium gas pressure is recorded. This may be achieved by extension of a calibrated quartz spring used to suspend the pan containing the sample.
Que.: Discuss in detail about the solid/ Gas interface
Que.: How will you determine dipole moment.
- The dipole moment of substance can be experimentally determined with the help of an electrical condenser. The parallel plates of the condenser can be charged by connecting them to storage battery. When the condenser is charged, an electric field is set up with field strength equal to the applied voltage (V) divided by distance (d) between the plates.
- The dipoles (polar substances) when placed between the changed plates, will rotate and align with the negative and towards positive plate and positive and towards the negative plate. Thus, all the molecules will align themselves in the electric field.
- The plates are charged to a voltage V before the introduction of the polar substance. They are then disconnected from the battery.
Que.: What do you understand by dipole moment? Write its applications.
Dipole Moment:
- When non-identical atoms (A and B) are joined by covalent bond, the pair of electrons will be attracted more strongly to the atom that has higher electronegativity.
- If A is more electronegative than B, it has a higher tendency to attract electrons. Thus, the shared pair of electrons it drawn near A leaving a positive charge on the B atom e.g., in a molecule such as HCl the bonding electron pair is not shared equally between hydrogen and chlorine atom.
- The chlorine with greater electro-negativity pulls the electron pair towards it. This gives a slightly positive charge (+ q) to the hydrogen atom and slightly negative charge (- q) to the chlorine atom.
Such a molecule with positive charge at one end and the negative charge at the other end is referred to as an electric dipole or dipole and it is said to possess a dipole moment (u).
- The dipole moment (H) is a product of the charge at one end and the distance between the opposite charges.
The CGS unit for dipole moment is the debye, symbolized as D. The dipole moment is a vector quantity.
Que.: How will you determine dipole moment.
Que.: Define matter. Classify matter on the basis of its state.
Matter: Matter can be defined as a substance that has a mass and that requires space. The matter is made up of infinitesimally small atoms, which are in a continuous state of motion.
Classification of matter on the basis of state:
Matter can be classified on the basis of state into three categories :
Gas: It consists of molecules separated wide apart in empty spaces. These molecules are free to move in the container.
(ii) Liquid: The molecules in a liquid are comparatively closer to each other than gaseous molecules. They also have the freedom of movement within the system.
(iii) Solids: The molecules, atoms or ions are arranged in a certain order in fixed positions in the crystal lattice. They however do not have the freedom of movement.
Que.: How the Changes occur in the states of matter?
Changes in the States of matter:
• Changes can occur in the states of matter either by heating or cooling. It can result in a physical or chemical change.
Physical change is that when only the state of the substance changes, without any change in the chemical composition.
- The process in which solid changes to a liquid is called as melting.
- The process in which liquid changes to a solid is called as freezing.
- The process in which liquid changes to a vapour is called as evaporation.
- The process in which vapour changes to a liquid is called as condensation.
- The process in which solid changes to a vapour is called as sublimation.
- Chemical change occurs when a substance changes into a new substance. It is indicated by change in the density, melting point of the original substance.
Que.: What do you understand by vapour pressure? Discuss factors affecting it.
Vapour Pressure:
When a liquid is placed in an open vessel, it evaporates. The molecules of a liquid move with different kinetic energies. Those molecules which possess higher kinetic energies manage to overcome the intermolecular forces holding them in a liquid and thus escape from the liquid surface as vapours. The process by which the molecules of a liquid go into the gaseous state is called vaporisation or evaporation.
If the liquid is placed in a closed vessel, the vapours escape into the empty spaces above the liquid but as the concentration of the liquid molecules in the empty spaces increases the molecules strike on the walls of the vessel and get converted back into liquid. This process is called as condensation. Thus a dynamic equilibrium is established between the liquid and vapour at a given temperature. Now the concentration of the vapour in. the space above the liquid remains unchanged with the lapse of time. This vapour will exert a definite pressure at equilibrium. The pressure exerted by the vapour in equilibrium with the liquid is called as vapour pressure.
Factors affecting vapour pressure:
Factors affecting vapour pressure are discussed as follows:
Nature of the liquid: The vapour pressure exerted by a liquid depends on its nature. Liquids with a low boiling point will have a high vapour pressure.
Intermolecular forces of attraction: Liquids with weak intermolecular forces of attraction evaporate faster and then have a high vapour pressure.
Temperature: If the temperature of the liquid increases, the vapour pressure also increases. An increase, in temperature increases the kinetic energies of more molecules and hence more of them leave the liquid thereby increasing the vapour pressure.
Que.: What is the Educational Qualification for SSC CHSL?
Que.: Describe in brief about sublimation.
Sublimation:
Sublimation is the transition of a substance directly from the solid to the gas phase, without passing through the intermediate liquid phase.
It is an endothermic process that occurs at temperatures and pressures below a substance's triple point in its phase diagram, which corresponds to the lowest pressure at which the substance can exist as a liquid.
The reverse process of sublimation is deposition or desublimation, in which a substance passes directly from a gas to a solid phase.
Sublimation has also been used as a generic term to describe a solid-to-gas transition (sublimation) followed by a gas-to-solid transition (deposition).
The term sublimation refers to a physical change of state and is not used to describe the transformation of a solid to a gas in a chemical reaction. For example, the dissociation on heating of solid ammonium chloride into hydrogen chloride and ammonia is not sublimation but a chemical reaction.
Sublimation is caused by the absorption of heat which provides enough energy for some molecules to overcome the attractive forces of their neighbours and escape into the vapour phase.
Since the process requires additional energy, it is an endothermic change.
The enthalpy of sublimation (also called heat of sublimation) can be calculated by adding the enthalpy of fusion and the enthalpy of vaporization.
Que.: Give the statement and postulates of kinematic molecular theory of ideal gases.
• Maxwell and Boltzmann in 1859 developed a mathematical theory to explain the behaviour of gases. It is based on the concept that gas is made of a large number of molecules in a perpetual motion. This theory is therefore called as kinetic theory of gases.
The theory is based on the following assumptions:
1. A gas consists of extremely small discrete particles dispersed throughout the container.
2. Gas molecules are in constant random motion with high velocities.
3.Gas molecules can move freely, independent of each other.
4. There is no loss of kinetic energy of a molecule during a collision.
5. The pressure of a gas is due to the striking of gas molecules on the walls of the container.
6. The average kinetic energy molecules is the same at a given temperature.
Que.: Write the characteristics of gas.
Characteristics of gas: A gas consists of molecules separated wide apart in empty space.
They have the following characteristics:
- They have infinite expansibility. They expand to occupy the entire volume of the container in which they are stored.
- They can be compressed by application of pressure.
- They exert pressure on the walls of the container in all directions.
Que.: Describe in brief about sublimation.
Que.: Describe the methods for measuring vapour pressure
Methods for Measuring Vapour Pressure: Vapour pressure of liquids are measured by static and dynamic methods as follows:
1. Static method:
This is a simple method for determination of vapour pressure. A sufficient amount of liquid whose vapour pressure is to be determined is placed in the bulb connected to a mercury manometer and a vacuum pump. All the air from the bulb is removed with the help of the vacuum pump and the stop cock is closed. A part of the liquid evaporates. The system is then maintained at a fixed temperature for enough time for equilibrium. The difference in the levels of mercury in the manometer is equal to the vapour pressure of the liquid.
Dynamic Method:
An inert gas is passed through a given liquid at a constant temperature (T). The gas saturated with the vapour of the liquid leaves the flask at the exit tube. This method is particularly useful for liquids of low vapour pressure.
Que.: Discuss in brief about liquid complexes.
1. Complex liquids or liquid complexes are materials intermediate between conventional liquids and solids, displaying fluid-like as well as solid-like behaviour.
Examples are polymeric melts or solutions, glasses, gels, foams and granular matter. Many of these systems are inherently disordered and strongly heterogeneous with large fluctuations on a wide range of length and time-scales. Furthermore many complex fluids, such as glasses or gels, never relax to equilibrium, which makes a theoretical analysis difficult.
2. Thus, these are binary mixtures that have a coexistence between two phases: solid-liquid (suspensions or solutions of macromolecules such as polymers), solid-gas (granular), liquid-gas (foams) or liquid-liquid (emulsions). They exhibit unusual mechanical responses that are applied stress or strain due to the geometrical constraints that the phase coexistence imposes. They mechanical response includes transitions between solid-like and fluid-like. behaviour as well as fluctuations.Their mechanical properties can be attributed to characteristics such as high disorder, caging, and clustering on multiple length scales.
3. Shaving cream is an example of a complex fluid. Without stress, the foam appears to be a solid: it does not flow and can support (very) light loads.
However, when adequate stress is applied, shaving cream flows easily like.
a fluid.
Que.: Write short note on Liquid Crystals and Glassy states.
Liquid Crystals:
1. Liquid crystals (LCs) or mesomorphs are a state of matter which has properties between those of conventional liquids and those of solid crystals. For instance, a liquid crystal may flow like a liquid, but its molecules may be oriented in a crystal-like way.
There are many different types of liquid-crystal phases, which can be distinguished by their different optical properties (such as textures). The contrasting areas in the textures correspond to domains where the liquid-crystal molecules are oriented in different directions. Within a domain, however, , the molecules are well ordered. LC materials may not always be in a liquid-crystal phase (just as water may turn into ice or steam).
2. Liquid crystals can be divided into thermotropic, lyotropic and metallotropic phases. Thermotropic and lyotropic liquid crystals consists mostly of organic molecules, although a few minerals are also known.
Thermotropic LCs exhibit a phase transition into the liquid-crystal phase as temperature is changed. Lyotropic LCs exhibit phase transitions as a function of both temperature and concentration of the liquid-crystal molecules in a solvent (typically water).
Metallotropic LCs are composed of both organic and inorganic molecules, their liquid-crystal transition depends not only on temperature and concen-tration, but also on the inorganic organic composition ratio.
Glassy States:
1. Glass is a state of matter. Glasses combine some properties of crystals and some of liquids but are distinctly different from both. Glasses have the mechanical rigidity of crystals, but the random disordered arrangement of molecules that characterises liquids.
2. Glasses are usually formed by melting crystalline materials at very high temperatures. When the melt coils, the atoms are locked into a random (disordered) state before they can form into a perfect crystal arrangement.
3. As a liquid (at the melting temperature, Tm) is cooled from a high temperature, it may either crystallise or become super cooled. The particles (atoms, molecules or ions) forming crystalline materials are arranged in orderly repeating patterns, with elementary building blocks (unit cells extending to all three spatial
dimensions.
4.The structures of crystalline solids depends (predictably) on the chemistry of the material and the conditions of solidification (starting temperature and cooling rate, ambient pressures etc.) and can be described easily in detail. Super cooled liquids, on the other hand, demonstrate a rather intringing behaviour.
5. Upon further cooling below the T their particles progressively lose translational mobility, so that around the so called glass transition temperature (Ty) rearrangement to "regular" lattice sites is practically unfeasible; this behaviour is distinctive for the amorphous structures described as glasses or vitreous solids.
Que.: Describe the types of Liquid Crystals.
Types of Crystals: Types of crystals are described as belows:
1. Lyotropic Liquid Crystals
2. Thermotropic Liquid Crystals
3. Metallotropic Liquid Crystals
1. Lyotropic Liquid Crystals :
(i) A lyotropic liquid crystals consists of two or more components that exhibit-crystalline properties in certain concentration ranges.
(ii) In the lyotropic phases, solvent molecules fill the space around the compounds to provide fluidity to the system. In contrast to thermotropic liquid crystal, these lyotropic have another degree of freedom of concentration that enables them to induce a variety of different phases.
(iii) A compound that has two immiscible hydrophilic and hydrophobic parts within the same molecule is called an amphiphilic molecule.
(iv) Many amphiphilic molecules show lyotropic liquid-crystalline phase sequences depending on the volume balances between the hydrophilic part and hydrophobic part.
2. Thermotropic Liquid Crystals :
(i) Thermotropic phases are those that occur in a certain temperature range. If the temperature rise is too high, thermal motion will destroy the delicate cooperative ordering of the LC phase, pushing the material into a conventional isotropic liquid phase.
(ii) At too low temperature, most LC materials will form a conventional crystal. Many thermotropic LCs exhibit a variety of phases as temperature is changed.
(iii) Depending on the shape of liquid crystals they are of three types:
- Smectic phase-thread like
- Nematic phase-soap like
- Cholesteric phase-layered
3. Metallotropic Liquid Crystals:
- Liquid crystal phases can also be based on low-melting inorganic phases like ZnCl, that have a structure formed of linked tetrahedra and easily form glasses. The addition of long chain slap-like molecules leads to a series of new phases that show a variety of liquid crystalline behaviour both as a function of the inorganic-organic composition ratio and of temperature. This class of materials has been named metallo-tropic.
- Thus a metallotropic liquid crystal consists of metal ions incorporated into the liquid crystals.
Que.: Discuss the types of glassy states.
Types of Glassy States: Following are the different types of glassy states:
- Formation of glass from crystalline materials: Actual formation of a glass formed by melting crystalline materials at very high temperatures.
- Glassy states of polymers cooled below (Ts) : It consists of polymers which have been cooled below the glass transition temperature (Tg). Thus these structures consists of fibrous structures of carbon atoms with small lateral branches in the form of hydrogen atoms or more complex radicals.
- Glassy states of inorganic compounds: It consists of refractory inorganic compounds of multivalent elements. These glasses in the stabilized state have the most thermostable chemical structure e.g., Silicon dioxide SiO, is as important constituent of glass.
Que.: Discuss in brief about liquid complexes.
Que.: Define Complexation.
Complexation is the combination of individual atom groups, ions or molecules to create one large ion or molecule. One atom or ion is the focal point of the complex. This central atom contains empty electron orbitals that enable bonding with other atoms as well as unshared electrons.
Que.: What are Chelate compounds and Chelation?
Chelate, any of a class of coordination or complex compounds consisting of a central metal atom attached to a large molecule, called a ligand in a cyclic or ring structure. An example of a chelate ring occurs in the ethylenediamine-cadmium complex.
Chelation: It is the formation or presence of two or more separate coordinating bonds between a polydentate (multiple bonded) ligand and a single central atom.
Que.: What are Chelating agents ?
Chelation is a type of bonding of ions and molecules to metal ions. It involves the formation or presence of two or more separate coordinate bonds between a polydentate ligand and a single central atom. These ligands are called chelants, chelators, chelating agents or sequestering agents.
Que.: Name the intermolecular forces required for complex formation.
(ii) Van der Waals forces
(iii)Ion dipole, dipole-dipole and dipole induced dipole
(iv) Hydrogen bonding.
Que.: What are the different types of inclusion complexes? Give example of each type.
Different types of inclusion complexes and their examples are as follows:
(i) Channel lattice type- Paraffins in deoxycholic acid
(ii) Layer type - Montmorillite clays
(iii) Clathrates - Warfarin sodium
(iv) Manomolecular type - Drug in B-cyclo-
dextrin.
Que.: Enlist the methods for determination of complexes.
The methods for determination of complexes are as follows:
- Method of continuous variation
- pH titration method
- Solubility method
- Distribution method.
Que.: What do you mean by protein binding ? Give two examples of protein binding.
The binding of drug or any compound to proteins in the body is called as protein binding.
Example: Binding of drug to albumin and binding of drug to a and glycoprotein.