300+ REAL TIME Pulp & Paper Objective Questions & Answers 2023

250+ TOP MCQs on Control Additives and Answers

Pulp and Paper Multiple Choice Questions on “Control Additives”.

1. Residue is a measure of how much material remains on the paper machine wire and is incorporated into the final sheet.
a) True
b) False
Answer: b
Clarification: Retention is a measure of how much material remains on the paper machine wire and is incorporated into the final sheet.

2. What is the name of the hidden part?

___________= {(filler in sheet) / (filler added to furnish)} x 100%

a) Drainage aids
b) First-pass retention
c) Residue
d) Overall retention
Answer: d
Clarification: Overall retention and first-pass retention. These are defined below in the terms of filler, although the retention of fiber fines, sizing agents, and other materials is also crucial.

3. What is the name of the hidden part?

_________= {(filler in sheet) / (filler in heatbox)} x 100%

a) Residue
b) Overall retention
c) First-pass retention
d) Drainage aids
Answer: c
Clarification: A high first-pass retention is important for many aspects of wet end chemistry and sheet quality.

4. _________ are materials that increase the drainage rate of water from the pulp slurry on the wire.
a) Overall retention
b) First-pass retention
c) Residue
d) Drainage aids
Answer: d
Clarification: Drainage aids are materials that inc. the drainage rate of water from the pulp slurry on the wire. Almost any retention aid is opted to improve the drainage rate as fines and fillers are removed.

5. _________are additives used to promote dispersion of fibers which improves formation and could allow higher headbox consistencies.
a) Overall retention
b) First-off retention
c) Formation aids
d) Drainage aids
Answer: c
Clarification: Formation aids are additives used to promote dispersion of fibers which improves formation and could allow higher headbox consistencies. There’s very less information on formation aids in the literature.

6. _________ are utilized to control foaming. Foam exists when some other insoluble gas is mixed into water containing surfactants, which is, surface active agents.
a) Overall retention
b) Defoamers
c) Drainage aids
d) Formation aids
Answer: b
Clarification: Defoamers are utilized to control foaming. Foam exists when air or some other insoluble gas is mixed into water which contain surfactants, which are, surface active agents. Soaps and detergents are good examples of surfactants.

7. Inorganic deposits could frequently be controlled with sequestering agents for the metal ions to keep them in solution by binding them to polar molecules.
a) True
b) False
Answer: a
Clarification: Chemicals are frequently utilized to control organic or inorganic deposits. Inorganic deposits could frequently be controlled with sequestering agents for the metal ions to keep them in sol. by binding them to polar molecules. Sequestering agents include chelants and threshold inhibitors, Chelants such as E.D.T.A., N.T.A., and D.T.P.A. react stoichiometrically.

8. Microorganisms, particularly bacteria and fungi, would grow around the paper machine and produce _________ which consists of proteins and polysaccharides.
a) Slime
b) Spot
c) Crisp
d) Buffer
Answer: a
Clarification: These are very identical to those utilized in bleaching mechanical pulps where metal ions can decompose H₂O₂ or cause discoloring of the pulp by reacting with phenolic compounds.

9. What is the name of the compound?

a) Quaternary ammonium salts
b) Glutaraldehyde
c) Isothiazolin
d) Dibromonltrilepropionannide
Answer: b
Clarification: Glutaraldehyde’s an organic compound with the formula CH₂(CH₂CHO₂. A pungent colorless oily liquid, glutaraldehyde’s utilized to sterilise medical and dental equipment. It is also utilized for industrial water treatment and as a preservative.

10. What is the name of the compound?

a) Dibromonltrilepropionannide
b) Isothiazolin
c) Glutaraldehyde
d) Quaternary ammonium salts
Answer: a
Clarification: D.B.N.P.A. or 2,2-dibromo-3-nitrilopropionamide’s a quick-kill biocide that easily hydrolyzes under both acidic and alkaline conditions. It’s opted for its instability in water as it quickly kills and then quickly degrades to form a number of products, depending on the conditions which include ammonia, bromide ions, dibromoacetonitrile, and dibromoacetic acid.

250+ TOP MCQs on Chlorine Bleaching and Answers

Pulp and Paper Multiple Choice Questions and Answers (MCQs) on “Chlorine Bleaching”.

1. The pH is of utmost importance in _________ for several reasons. First the form of Cl in solution is dependent on the pH according to the following equilibrium reactions.
a) Chlorine bleaching
b) Peroxide bleaching
c) Alovera bleaching
d) Milk bleaching
Answer: a
Clarification: The pH is of utmost importance in chlorine bleaching for several reasons. First the form of Cl in solution is dependent on the pH according to the following equilibrium reactions.

2. The concentration of Cl in water at 25°Celcius is _________ at saturation (i.e., 1 atmosphere pressure of CI₂).
a) 1.254 M
b) 5.324 M
c) 0.091 M
d) 4.542 M
Answer: c
Clarification: The concentration of Cl in water at 25°Celcius is 0.091 M at saturation i.e., one atmosphere pressure of CI₂. Like the solubility of CO₂, the solubility of CI₂ is highly pH dependent.

3. A saturated chlorine solution in water, with addition of acid or base, has a pH of or 1.54, an actual chlorine concentration, Cy, of 0.062 M, a hydrochloric acid concentration of 0.029 M, and HOCl concentration of 0.029.
a) True
b) False
Answer: b
Clarification: Therefore, a saturated Cl solution in water, without addition of acid or base, has a pH of 1.54, an actual Cl concentration, Cy, of 0.062 M, a HCl concentration of 0.029 M, and a HOCl concentration of 0.029.

4. An eq. is easily solved at various pH is by utilization of the quadratic eq. At pH = 0, X = 0.00423 M. At pH 1.66, x = 0.0222 in agreement with the calc. above.
a) True
b) False
Answer: a
Clarification: This eq. is easily solved at various pH is by use of the quadratic equation. At pH = 0, X = 0.00423 M. At pH 1.66, x = 0.0222 in agreement with the calc. above.

5. The pH at intermediate amounts of base is given in the form of the _________equation; consequently, the ratio of HOCI to OCl^– is not concentration dependent.
a) Henderson-Hasselbalch
b) Kennedy-kraft
c) Jason-Hammer
d) Leigh-Mark
Answer: a
Clarification: The pH at intermediate amounts of base is given in the form of the Henderson-Hasselbalch equation; consequently, the ratio of HOCI to OCl^– is not concentration dependent except for the effect of activity coefficient from pH 5 to 9.

6. The desired reaction of substitution occurs most rapidly at the _________ pH values; however, acid hydrolysis of cellulose and hemicellulose also increases with decreasing pH.
a) High
b) Slightly above neutral
c) Slightly below neutral
d) Low
Answer: d
Clarification: The desired reaction of substitution occurs most rapidly at the lowest pH values; however, acid hydrolysis of cellulose and hemicellulose also increment with decreasing pH. Acid hydrolysis leads to a decrement in the cellulose viscosity.

7. The hydrolysis of chlorine is also temperature dependent. _________ in Pulping Processes gives the hydrolysis constants of CI₂ as a function of temperature; they are 1.45 x 10^-4 at 0°C and 9.75 x 10-4 at 60°C.
a) Francis
b) Walter
c) John
d) Rydholm
Answer: d
Clarification: The hydrolysis of chlorine is also temperature dependent. _________ in Pulping Processes gives the hydrolysis constants of CI₂ as a function of temperature; they are 1.45 x 10^-4 at 0°Celcius and 9.75 x 10^-8 at 60°Celcius.

8. Fill in the blank.

K = (_________ x²) / (0.05 – x)

[H⁺] + K₁x – 0.05K₁ = 0

a) [H⁺].

b) [HOCl]

c) K₁

d) K₂
Answer: a

Clarification: The ratio of CI₂ to HOCl as a function of pH where the source of the acid is immaterial is solved in the following manner, where x = [HOCl] = [CI]. At pH = 0, X = 0.00423 M.

9. Fill in the blank.
K_a = [H⁺][Cl^–] / [Cl₂] = ([H⁺]³) / (0.091 – [H⁺])
a) [H⁺].

b) [HOCl]

c) K₁

d) K₂
Answer: b
Clarification: The concentration of chlorine in water at 25°C is 0.091 M at saturation (i.e., one atmosphere pressure of CI₂). (Like the solubility of CO₂, the solubility of CI₂ is highly pH dependent.). Solving for [H⁺] gives [H⁺] = 0.029 M. Therefore, a saturated chlorine solution in water, without addition of acid or base, has a pH of 1.54, an actual chlorine concentration, [Cy, of 0.062 M, a hydrochloric acid concentration of 0.029 M, and a hypochlorous acid concentration of 0.029 M.

10. Fill in the blank.
pH = pK_a + log (C_A- / C_A)

= 7.46 + log ([OCl^–]) / (____________)

a) [H⁺]

b) [HOCl]

c) K₁

d) K₂
Answer: b
Clarification: The pH at intermediate amounts of base is given in the form of the Henderson-Hasselbalch equation; consequently, the ratio of HOCI to OCl^– is not concentration dependent (except for the effect of activity coefficients) from pH 5 to 9.

250+ TOP MCQs on Polymeric Additives and Answers

Pulp and Paper Multiple Choice Questions and Answers (MCQs) on “Polymeric Additives”.

1. Paper making polymers can be categorized as naturally occurring polymers, modified naturally occurring polymers, and synthetic polymers.
a) True
b) False
Answer: a
Clarification: They may also be classified as neutral, cationic, anionic or zwitterions. The widely utilized natural paper making polymers are polysaccharides or proteins.

2. The term _________is often utilized to mean a material containing cationic and anionic groups; strictly speaking, however, it means a material that is both acidic and basic.
a) Amphoteric
b) Zwitter ion
c) Neutral
d) Cationic
Answer: a
Clarification: If compound is a molecule or ion that can react both as an acid and a base.HCO₃^– is amphoteric; it isn’t a zwitterion.

3. A molecule with only carboxylic acid is amphoteric and a zwitterion.
a) True
b) False
Answer: b
Clarification: It is not strictly amphoteric, since the sulfonate is the conjugate base of a strong acid and not appreciably basic. A molecule with an amine and a sulfonate exists as a zwitterion.

4. Polymers with charged groups are called _________
a) Amphoteric
b) Zwitter ion
c) Neutral
d) Poly electrolytes
Answer: d
Clarification: Anionic groups are usually carboxylates and occasionally sulfonates or phosphates. Cationic groups are usually amines or quaternary ammonium salts or quats.

5. A high charge density (above the 30% level) tends to completely unravel the normally coiled molecules in solution. What’s the criteria discussed here?
a) Poly electrolytes
b) Charge density
c) Zwitter ion
d) Amphoteric
Answer: b
Clarification: The charge density calculated as the percentage of monomers containing a charge is an crucial criterion for polyelectrolytes. The electric charge / unit area of a surface, or / unit volume of a field or body.

6. _________ are relatively inexpensive polymers that are easily devised to high molecular weights on the order of several million (g/mol).
a) Poly electrolytes
b) Polyacrylamimdes
c) Charge density
d) Carboxylate
Answer: b
Clarification: It is a polymer (-CH2CHCONH2-) which are formed from acrylamide subunits. It could be formed as a simple linear-chain structure or cross-linked.

7. Anionic _________ usually contains about 5% polyacrylic acid groups formed by co-polymerization of acrylamide and acrylic acid monomers or by hydrolysis of P.A.M. homopolymer under conditions to convert some of the amide groups to carboxylate salts.
a) Poly electrolytes
b) Polyacrylamimdes
c) Charge density
d) Carboxylate
Answer: b
Clarification: Polyacrylamide could be supplied in a powder or liquid form, with the liquid form being subcategorized as solution and emulsion polymer. This process applies to water treatment, and processes like paper making and screen printing.

8. Potato _________ has about 0.1 to 0.3% equivalent PO₄ corresponding to a degree of substitution of 0.002 to 0.005.
a) Starch
b) Lignin
c) Pulp
d) Protein
Answer: a
Clarification: Potato starch has little protein, while corn starch is about 0.3% protein. These granules and the starch therein are made soluble by the cooking process. Starch is a polymeric carbohydrate which consists a large number of glucose units which are joined by glycosidic bonds.

9. _________ reactions of secondary and primary amines are analogous where 1 or 2, respectively, of the R groups are protons.
a) Acid dissociation
b) Base dissociation
c) Cationic association
d) Anionic association
Answer: a
Clarification: An acid dissociation constant, Ka is also known as acidity constant. It is a quantitative measure of the strength of an acid in the solution. Protonated trimethylamine has a pKa of 9.80 and triethylamine has a pKa, of 10.72.

10. _________ serves as a model compound for the acid ionization behaviour of many carboxylic acid groups.
a) Hydroxylic acid
b) Sulphuric acid
c) Acetic acid
d) Nitric acid
Answer: c
Clarification: It has a distinctive sour taste and pungent smell. It’s classified as a weak acid, concentration acetic acid is corrosive and can attack the skin.

250+ TOP MCQs on Kubelka-Munk Theory and Answers

Pulp and Paper Multiple Choice Questions on “Kubelka-Munk Theory”.

1. The crucial optical properties include reflectance colour and brightness, especially diffuse reflectance and opacity.
a) True
b) False
Answer: a
Clarification: The optical properties of paper are extremely crucial for many of its utilizes, especially when paper is utilized for printing. Most crucial ones are reflectance colour and brightness, especially diffuse reflectance and opacity.

2. A normalized approach to the optical properties of paper allows one to predict the properties of paper to avoid a labour intensive trial—and—error work approach.
a) True
b) False
Answer: a
Clarification: Optical projection tomography (O.P.T.) is a recently introduced 3-dimensional imaging technique for primary utilize the developmental biology and gene expression studies.

3. Paper with 85.0% reflectance relative to a certain MgO standard that is known to have an absolute reflectance of 0.980 corresponds to an absolute reflectance of ___________
a) 0.833
b) 1.25
c) 6.35
d) 0.687
Answer: a
Clarification: Absolute reference is calculated as 0.850 x 0.980 = 0.833

4. ___________ is the property of a material that indicates the ability to hide what is behind it.
a) Transparency
b) Opacity
c) Glossiness
d) Reflectivity
Answer: b
Clarification: Opacity is the calculation of impenetrability to electromagnetic or other kinds of radiation, especially visible light. In radiative transfer, it tells about the absorption and scattering of radiation in a medium, such as a plasma, dielectric, shielding material, glass, etc.

5. The reflectance of an (effectively infinite) thick pad of paper is R1 and is known as ___________
a) Transparency
b) Opacity
c) Glossiness
d) Reflectivety
Answer: d
Clarification: It is the fraction of incident electromagnetic power that’s reflected at an interface. The reflectance of a single sheet with a perfectly white backing is given as R1 and the corresponding opacity is called the ideal opacity.

6. If one knows the ___________ and reflectivity of a paper, the changes in these properties with a change could be predicted.
a) Weight ratio
b) Contrast ratio
c) Curtis ratio
d) Kraft ratio
Answer: b
Clarification: It’s the ratio of the luminance of the brightest color to that of the darkest color that the system is capable of giving out. A high contrast ratio’s a required aspect of any display.

7. The Kubelka—Munk theory of light allows one to predict quantitatively the behaviour of light in coatings such as ___________ for which it was developed; this work has become the basis of much of this field.
a) Thinner
b) Paper
c) Paint
d) Plastic
Answer: c
Clarification: Kubelka—Munk theory is utilized in papermaking in many ways. If one knows the optical properties of each pulp, filler, and dye utilized in papermaking, then the optical properties of a paper made with any combination of the materials could be predicted. If one knows the contrast ratio and reflectivety of a paper, the changes in these properties with a change in basis weight could be predicted.

8. The Kubelka—Munk theory was developed to define properties based on the thickness of a material (X), but in the case of porous materials like ___________ workers quickly started utilizing basis weight.
a) Thinner
b) Paper
c) Paint
d) Plastic
Answer: b
Clarification: It isn’t terribly good for dyed papers when light absorption reaches a greater level. A limiting assumption is that the particles making up the layer must be much less than the total thickness.

9. _____________ filters could be utilized to remove the effect of gloss light reflected according to Fresnel’s law which has a degree of polarization.
a) Polarized
b) Doped
c) Magnified
d) Electrocuted
Answer: a
Clarification: The ability of waves to oscillate in more than a single direction; in particular polarization of light, responsible for example for the glare-reducing effect of polarized sunglasses.

10. What is the name of the equation?

S_p = (S-(1-y)S_f) / (y)

a) Steele
b) Kraft
c) Michaud
d) Tomas
Answer: a
Clarification: Steele in 1937 gave the calculation to determine the scattering coefficient of the pigment filler in the filled paper as a function of the scattering power of the fiber, the scattering coefficient of the filled paper (5), and the fraction of filler in the filled sheet (y).

250+ TOP MCQs on Pulping and Answers

Pulp and Paper Multiple Choice Questions on “Pulping”.

1. Pulp consists of 2 things which are, wood and the libocellulosic materials that are broken down physically and chemically.
a) True
b) False
Answer: a
Clarification: Pulp consists of wood and lignocellulosic materials that has been broken down physically and chemically.

2. Which are 4 broad categories of pupling processes?
a) Chemical, semi-chemical, chemi-mechanical, and mechanical
b) Qualitative , semi-chemical, chemi-mechanical, and mechanical
c) Quantitative, semi-chemical, chemi-mechanical, and thermal
d) Isentropic, semi-chemical, chemi-mechanical, and mechanical
Answer: a
Clarification: Following are the four broad categories of pulping:
Chemical, semi-chemical, chemi-mechanical, and mechanical.
These are in increasing order of mechanical energy required to separate fibers and decreasing reliance on chemical action.

3. Wood-free pulps contain no mechanical pulp or contains pulp subjected to a min. refining.
a) True
b) False
Answer: a
Clarification: Wood-free pulp contains no mechanical pulp or contains pulp subjected to a minimum of refining; consequently, at the time of its manufacturing the water drains from the pulp on the Fourdrinier wire.

4. ____________ is the process whereby the pulp is separated from large shives, knots, and etc.
a) Shredding
b) Cutting
c) Picking
d) Screening
Answer: d
Clarification: Screeing is the process whereby pulp’s separated from the large shives, knots, and etc. It contains accepts and rejects for further distinguishing.

5. ___________ are small finer bundles of fibers that have not been separated into individual fibers during the pulping process.
a) Shives
b) Yield
c) Grains
d) Pulp
Answer: a
Clarification: Shives are small finer bundles of fibers that have not been separated into individual fibers during the pulping process.

6. Which process is used to treat all types of woods for pulping process?
a) Mechanical pulping
b) Neutral-sulfite semi-chemical(N.S.S.C.)
c) Kraft process
d) Chemical mechanical pulping
Answer: c
Clarification: Chemicals used in this process are NAOH and Na₂S. it is used to treat all types of wood. The yield strength of this would be 65-70%.

7. How to calculate the total yield?
a) Screening (%) + Screened yield (%)
b) Dry solid mass (%) + Screened yield (%)
c) Screening (%) + Slurry mass (%)
d) Dry product mass out (%) + Dry product mass in (%)
Answer: a
Clarification: The total yield is equal to amount of pulp removed while screening and the yield of pulp after the screens when all 3 are expressed as a percentage of the original wood put in the digester.

8. How to calculate consistency?
a) (Dry solid mass) (slurry mass)^-1 x 100
b) (Dry solid mass)^-1 (slurry mass) x 100
c) (Dry solid mass) (slurry mass)^-2x 100
d) (Dry solid mass)^-2 (slurry mass) x 100
Answer: a
Clarification: Consistency is a measure of the solids content as a percentage in a pulp slurry.

9. How to calculate yield %?
a) (Dry product mass out) (Dry product mass in)^-1 x 100
b) (Dry product mass out)^-1 (Dry product mass out) x 100
c) (Dry product mass out) (Dry product mass out)^-2 x 100
d) (Dry product mass out)^-2 (Dry product mass out) x 100
Answer: a
Clarification: Yield % is a measure of the dry product mass content as a percentage in a pulp slurry.

10. Chemical pulping yields individual fibers that are not cut and give strong papers because of ________ as it interferes with hydrogen bonding is largely removed.
a) Pulp
b) Hydrogen
c) Phosphate
d) Lignin
Answer: d
Clarification: Chemical pulping yields individual fibers that are not cut and give strong papers since the lignin. Which interferes with hydrogen bonding is largely removed.

250+ TOP MCQs on Measurement of Lignin Content and Answers

Pulp and Paper Interview Questions and Answers for freshers on “Measurement of Lignin Content”.

1. The measurement of lignin in chemical pulps is a vital tool to monitor the degree of cook (extent of delignification during pulping).
a) True
b) False
Answer: a
Clarification: The measurement of lignin in chemical pulps is a vital tool to monitor the degree of cook (extent of delignification during pulping) to measure residual lignin before bleaching and the between various stages of bleaching to monitor the process.

2. To measure residual lignin prior to bleaching pulp brightness between bleaching stages are often used to control the bleaching operation.
a) True
b) False
Answer: a
Clarification: To calculate residual lignin prior to bleaching pulp brightness between bleaching stages are often used to control the bleaching operation.

3. Lignin is easily measured indirectly by measuring the amount of __________ consumed by lignin in a sample of pulp of known mass.
a) Anti oxidant
b) Oxidant
c) Pulp
d) Poison
Answer: b
Clarification: Lignin is easily measured indirectly by measuring the amount of oxidant (such as Cl ) consumed by lignin in a sample of pulp of known mass.

4. The __________ test is an indirect method for determining amount of lignin consumption of permanganate ion.
a) Alfa
b) Beta
c) Gama
d) Kappa
Answer: d
Clarification: The Kappa test is an indirect method used for determination. The kappa number is the number of milliliters of 0.1 KMn0₄ consumed by one gram of pulp in 0.5N sulftiric acid after a ten minute reaction time at 25°C under conditions such that one-half remains unreacted.

5. __________ lignin is considered to be the same as the actual lignin content. __________ % = 0.15 x kappa number.
a) Alander
b) Palenius
c) Kyrklund
d) Klason
Answer: d
Clarification: Klason lignin is considered to be the same as the actual lignin content. Alander, Palenius, and Kyrklund give the following relationship for sulfite and kraft chemical hardwood pulps: Klason lignin, % = 0.15 x kappa number.

6. A 40 ml K no. of 10 corresponds to a kappa no. of 14.5, 20 corresponds to 30.4 kappa number, and 30 corresponds to __________ kappa number.
a) 64.1
b) 32.1
c) 85.1
d) 95.1
Answer: a
Clarification: log (kappa no.) = 0.837+ 0.0323 (40 ml K no.)

7. The __________ is a measurement of lignin content by the number of grams of gaseous Cl₂ consumed by 100 grams dry pulp at 25 °C in 15 minutes.
a) Row number
b) Roe number
c) Chloe number
d) Christ number
Answer: b
Clarification: The Roe number’s a measurement of lignin content by the number of grams of gaseous Cl₂ consumed by 100 grams dry pulp at 25 °C (77 °F) in 15 minutes.

8. The __________ is a test method just like that of Roe, except the CIO₂ is generated in sit by acidification of sodium hypochlorite.
a) Klason lignin
b) Kappa number
c) Chlorine number
d) Roe number
Answer: c
Clarification: The chlorine number is a test method just like that of Roe, except the CIO₂ is generated in sit by acidification of sodium hypochlorite.

9. Chlorine number = __________ x Roe number.
a) 0.10
b) 0.20
c) 0.80
d) 0.90
Answer: d
Clarification: The chlorine number is a test method, the CIO₂ is generated in sit by acidification of sodium hypochlorite. Chlorine number = 0.90 x Roe number.

10. __________ lignin is the residue extracted after the total acid hydrolysis of carbohydrate portion of wood. It’s a gravimetric method for determining lignin directly in woody materials.
a) Klason
b) Karlson
c) Klux
d) Kurl
Answer: a
Clarification: Klason lignin is the residue extracted after the total acid hydrolysis of carbohydrate portion of wood. It is a gravimetric method for determining lignin directly in woody materials.

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