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DAIRY CHEMISTRY

 

 

Physical Chemistry of Milk 

Compiled By : Mr. Abhay Pandey

Q. The milk constituent which is in highest concentration in the milk from all the species is

A. Water

 

Q. Lactose content will be highest in the milk produced by

A. Human

 

Q. The common name for the species Bubalus bubalis

A. Buffalo

 

Q. Mineral content in the milk is highest in the milk produced by

A. Sheep

 

Q. When one substance disperses evenly and thoroughly in to the other such

substances are known as

A. colloid

 

Q. When light rays pass through a colloidal system they will be

A. Completely scatter

 

Q. The basis for the Classification of the colloids is

A. Affinity with the dispersing molecules

 

Q. Particle size of the molecules which are dispersed in a colloid

A. Between 10(power) - 5 and 10(power) - 7 cm

 

Q. Surface tension of the lyophyllic colloidal molecules will be

A. Less than the dispersion medium

 

Q. The important milk constituent which influences the density of milk is

A. Fat

 

Q. The density of milk with an average composition will be

A.   1.030 kg/m3

 

Q. The instrument used for the determination of specific gravity of concentrated milk products is

A. Baume's meter

 

Q. During the refrigeration of milk the specific gravity will increase due to

A. Crystallization of fat

 

Q. The effect of homogenization of whole milk on the density is

 A. Slight increase

 

Q. The physical property of liquids useful in studying the stability of emulsions and colloids is

A. Surface active property.

 

Q. Surface energy for extremely fine emulsions will be higher because

A. Large surface area.

 

Q. The units used for expressing the surface tension in CGS units are

A. Dyne per cm

 

Q. The surface active substances concentrate at the surface in proportion to their

A. Ability to reduce the surface tension

 

Q. In milk the constituents which depresses the surface tension are

A. Proteins and lipids

 

Q. In fluids the resistance of liquid to flow or pour is known as

A. Viscosity

 

Q. The volume of the milk constituents considerd for determining the volume fraction of the dispersed particles are

A. Lactose

 

Q. When a plot of shear stress versus rate of shear is a straight line passing through the origin such fluids are known as

A. Newtonian fluids

 

Q. Among the milk and milk products the Newtonian behavior is exhibited by

A. Cream

 

Q. The milk product which exhibits the apparent viscosity is

A. Ice cream

 

Q. The effect of adding urea upto 4.8M to skim milk on its viscosity is

A. Initial increase followed by decrease

 

Q. The most important milk constituent contributing to its viscosity is

A. Casein micelles

 

Q. The most suitable instrument useful in measuring the viscosity of non Newtonian fluids is based on

A. Capillary tube

 

Q. The viscosity of skim milk is

A. 1.2 centipoise

 

Q. The viscosity of milk is often measured as

A. Relative viscosity

 

Q. Physical properties that depends only on the number of particles in solution rather than the type of particle are known as

A. Colligative property

 

Q. A membrane which separates two solutions with different concentration of solutes allows only water from the solution but not the solutes it is known as

A. Semi permeable membrane

 

Q. The temperature at which the vapor pressure of the liquid equals the surrounding pressure.

A. Boiling point

 

Q An increase in the amount of solute in a solution the melting point of thesolution will

A. Increase

 

Q. When an ionic material dissociate in to their ions the number of ions formed will be equal to the

A. Number of molecules present

 

Q. The process which is helpful in isolating some of the constituents which are in soluble state in milk is

A. Osmosis

 

Q. When a solution and the pure solvent used in making that solution are placed on either side of a

semi permeable membrane the side on which the pressure is exerted on the membrane will be

A. Solution side

 

Q. The law expressed by the equation P = solvent Po is

A. Raoult's law

 

Q. The effect of adding a nonvolatile solute to a liquid on the vapor pressure above that solution is

A. Decrease

 

Q. Equilibrium vapor pressure above the pure liquid will be established by

 A Both the escaping and entrapping of the gaseous molecules

 

Q. Boiling point of milk is higher than that of water because of the presence of

A. lactose

 

Q. Milk which is adulterated with water will have a boiling point

A. Lower than milk boiling point

 

Q. Boiling point of normal cow milk

A. 100.15 (Degree)C

 

Q. The freezing point of milk obtained from an animal affected with mastitis will be

A. Similar to the normal milk

 

Q. The temperature at which the solid, liquid and vapour pressure exists in equilibrium with each other is known as

A. Freezing point

 

Q. The substances which does not increase the collegative property when dissolved in water are known as

A. Non- electrolytes

 

Q. The theory of electrolytic dissociation or ionization was proposed by

A. Arrhenius

 

Q. Electric current in a solution is conducted by the.

A. Migration of ions

 

Q. An ion will have a negative charge when its nucleus has

A. More electrons

 

Q. The ultimate unit of electricity and its charge is

A. Electron, negative charge

 

Q. The theory of electrical dissociation is proposed by

A. Arrhenius

 

Q. The ionic conductances are proportional to their

A. Ionic mobilities

 

Q. To which type of solutions A"the degree of dissociation is inversely proportional to the square root of the initial molar concentration

A. Weak binary electrolyte

 

Q. To which law the equation K =[A+][B-] / [AB] represents

A. Chemical equilibrium

 

Q. Ionic and polar substances are more easily soluble in polar solvents because they are

A  Easily ionizable

 

Q. Water molecules can form strong electrostatic attractions with other water molecules, polar molecules and ions because

A. Uneven distribution of electrons

 

Q. Pure water in its equilibrium state the concentration of H3O+ and OH- will be

A. Both the ions are Equal

 

Q. Concentration of unionized water is taken as constant because

A. Poor dissociation of molecules

 

Q. The substances in which ionization can be induced are known as

 A. Ionic substances

 

Q. In solutions containing acids the equilibrium of the water dissociation will be affected due to

A. Formation of H+ ions

 

Q. The equilibrium is determined by the dissociation constant which in general is expressed in terms of their activities and it is known as

A. Ionic product of water

 

Q. The number of moles of water per L at 25 degree C are

A. 55.5

 

Q. The negative common logarithm of the concentration of OH-: is defined as

A. pOH

 

Q. The product of [H+] and [OH-] is always equal to

A. 10-14

 

Q. According Lewis concept an acid is any species which is capable of

A. Accepting a pair of electrons

 

Q. An example for Lewis acids which have the electro deficient molecules is

A. AlCl3

 

Q. According to Bronsted -Lowry the process in which a proton is transferred from an acid to a base is known as

A. Neutralization

 

Q. Water can act both as an acid as well as a base because it can

A. Accept and also give off protons

 

Q. As proposed by the Arrhenius the substances that produce protons H+ and bases are the substances which produce OH- in the media

A. Water

 

Q. The proportion of the reagents and products at equilibrium can be obtained by using an

A. Equilibrium constant

 

Q. The range of dissociation constant( Ka ) for acids will be

A. 10-12 to 10-13

 

Q. The higher value for the equilibrium constant indicates that the given acid is

A. Strong

 

Q. The undissociated molecules in weak acids when compared to the dissociated particles will be

A. Very high

 

Q. In milk the change in the pH would result in the change of

A. Destabilize the proteins

 

Q. The pH of normal healthy cow milk will range between

A. 6.5 to 6.8

 

Q. The pH of the milk does not truly represent the titratable acidity because

A. Non availability of ionic groups of proteins for titration

 

Q. In the freshly drawn milk the acidity caused by the constituents of the milk is known as

A. Apparent acidity

 

Q. Total titratable acidity of fresh milk is useful for

A. Determining the heat stability

 

Q. The reaction of acids with bases will result in the formation of

A. Salt

 

Q. The process that would occur when the salts come in contact with water is known as

A. Hydrolysis

 

Q. The reaction of a weak base with a weak acid will result in the

A. Salt formation

 

Q. The effect of adding a strong base to an acid buffer is the formation of

A Equal amount of salt

 

Q. A basic buffer is a combination of weak base (BOH), and its salt with

A. Strong acid

 

Q. A solution containing relatively large amounts of a weak base and its salt with a strong acid, is termed as

A. Basic buffer

 

Q. When compared with the fluids surrounding the fluid cells within the cell have to maintain

A. Same pH

 

Q. The symbol used for the expression of dissociation constant of an acid is

A. pKa

 

Q.It is possible to calculate the ratio of concentrations of acid and conjugate base, necessary to prepare the buffer using the HendersonA-Hasselbalch equation

A. Dissociation constant of the acid and pH

 

Q. The factors which help for assessing the aggregation or dispersion of protein micelles and fat globules is by knowing the

A. Buffering index

 

Q. The molar quantity of acid or base needed to change the pH by one unit is known as

A. Buffering index

 

Q. The maximum buffering index of standardize milk with 3.0% fat is

A. 0.0283

 

Q. The colloidal calcium phosphate in milk becomes soluble when

A. pH is Lowered

 

Q. For the dissociation process of the compounds like sodium chloride the energy required for the ions is obtained by the process of

A. Hydration.

 

Q. The results obtained by using the color indicators will be

A. Very close to real value

 

Q. pH indicators being weak acid or base upon addition to a solution they will

A. Bind the H+ of OH- ions

 

Q. The indicators that exhibit several smooth colour changes over wide range of pH values are known as

A. Universal indicators

 

Q. The natural source for Anthocyanins, an extractable red pigment is

A. Red cabbage

 

Q. Measuring the tendency of a chemical species to acquire electrons and to get itself reduced is known as

A  Oxidation reduction potential

 

Q. Electrochemical cells are powered by redox reactions and produce which are spontaneous electricity are known as

A. Galvenic cell

 

Q. The electrodes which are fast, very selective, used in vivo are

A. Biosensor Membrane Electrodes

 

Q. The electrodes which are reversible, which follow Nernst equation and have stable potential with time are

A. Reference electrodes

 

Q. The equation developed by Nernst is useful for the calculation of

A. The electrode potential

 

Q. The principal systems that determine the Eh of milk is

A.  Ascorbate

 

Q. The effect of removing the oxygen in the system and introducing the Nitrogen gas in to milk on the Eh of milk is

A. Decrease

 

Q. The ascorbic acid content of fresh milk is about

A. 0.25 mEq/L

 

Q. The process by which the ascorbate content of milk can be preserved is by

A. Deaeration

 

Q.The range of Eh where the Methylene blue reduction noticed is

A. +0.12 to +0.03V

 

Q. The process of using sustained nuclear fission for gernerating heat and electricity is known as

A. Nuclear power

 

Q. Due to the emission of alpha rays an atom will lose two protons and the atomic number by two units and the element is said to be undergoing

A. Transmutation

 

Q. The reaction where two or more elements "fuse" together to form one larger element is known as

A. Nuclear fusion

 

Q. Atoms having the same nuclear charge but are having different masses are known as

A. Isotopes

 

Q. The emission of electromagnetic energy (Similar to light energy) from an atom A's nucleus is known as

A. Gama radiation

 

Q. The time taken for the radio nuclide to lose half of its radioactive property is known as

A. Half life

 

Q. The oldest and cost effective method used to detect the radiation exposure from alpha, beta and x-rays is

A. Film badge

 

Q. In comparison to a radio nuclides having shorter half life, a longer half life radio nuclide the power of a radioactivity will be

A. Lesser

 

Q. The field in which the dose calibrators and pocket dosimeters are used in ionization chamber of a radioactivity measuring instrument is

A. Medicine

 

Q. The source of entry of radionuclide in cow milk is

A. Pasture grass

 

Q. The time taken for half of the radio active element ingested by a person has been excreted is known as

A. Biological half life

 

Q. In our Country the level of radioactive minerals in milk and milk products when compared with the recommended limits of a country are

A. Lower

 

Q. Electromagnetic radiation is classified on the basis of

A. Wave length

 

Q. When the electromagnetic radiation interacts with single atom and molecules their behavior depends on the

A. Energy carried by them

 

Q. The instrument used for the detection of radiation is

A. Spectroscope

 

Q. By using the high induced current the radiation obtained will produce heat which is used in

A. Microwave heating

 

Q. The law which shows relationship between the absorption of light and to the properties of the material through which the light is travelling is

A. Lambert-beer

 

Q. Term used to describe the shift of absorption to a longer wavelength in the UV-visible spectroscopy is

A. Bathochromic

 

Q. The Beer's law is useful for measuring the

A. Absorbance

 

Q. The most commonly used solvent for the UV-visible spectroscopy is

A. Ethanol

 

 

Reference:-

 

1.      ICAR  E-course

2.       NDRI class notes

3.      Previous year question papers

 

 


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