This set of Basic Pulp and Paper Questions and Answers focuses on “Wood Chemistry”.
1. Cellulose is a material which can exist in crystalline and amorphous states
Explanation: It is a white solid material that exists in both the states. It is about 50 – 70% crystalline and forms the “back-bone” structure of wood fiber.
2. Which is the part where lignin is highly concentrated?
a) Outskirts of lamella
b) Middle lamella
Explanation: Lignin is more highly concentrated in the middle lamella and primary cell wall regions of the wood fiber than any other part of cell wall.
3. Cellulose is a linear polymer of anhydro-D-glucose connected by beta-(1-4)-linkage?
Explanation: On the molecular level, cellulose is a linear polymer of anhydro-D-glucose connected by beta-(1-4)-linkage. The degree of freedom, which is the number of units (Glucose in this case) that make up polymer above 10,000 in unaltered wood.
4. What are the chemical elements present in wood?
a) C, O, H, N
b) Co2, O2, N2, H2
c) Co2, O2, N2, H
d) Co2, O2, N, H2
Explanation: The chemical components are carbon, oxygen, hydrogen, and nitrogen.
In the respective percentages 50%, 44.5%, 6.1%, and 0.5%.
5. Microfibrils occur in which section of cell wall?
Explanation: Microfibrils are oriented in different directions in each of three layers within secondary cell wall.
6. ___________ decreases the strength of pulp yield, and are not ideal for dissolving pulp process.
Explanation: Hemicellulose increase the strength of the paper and the pulp yield, especially tensile, burst, and fold.
7. Which of the following is a condensed polymer?
c) Hardwood hemicelluloses
Explanation: Hemicellulose are condensation polymers with a molecule of water removed with every linkage.
8. Which is the compound which is a complex polymer consisting of phenylpropane units and has an amorphous three-dimensional structure?
Explanation: Lignin is the compound which is a complex polymer consisting of phenylpropane units and has an amorphous three-dimensional structure. Its molecular weight in wood is very high and cannot be easily measured.
9. Which is the compound by definition are soluble in organic solvents, and water?
Explanation:Extractives are the compound of diverse nature with low to moderately high molecular weights, which by definition are soluble in organic solvents, and water. They impart colour, odor, taste, and ocassionaly, decay resisitance to wood.
10. Turpenes are made from _________ units in the living wood cell?
a) Sulphated isoprene
b) Phosphated isoprene
c) Carbonated isoprene
d) Hydrogenated isoprene
Explanation: Terpenes are a broad class of compounds appearing in relatively high quantities in the softwoods.
Sanfoundry Global Education & Learning Series – Pulp and Paper.
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