Pulp and Paper Multiple Choice Questions on “Selected Reactions of Carbohydrates”.
1. Acid hydrolysis becomes important in the pulp and paper industry whenever we process wood fibers below pH 2 or so at elevated temperatures.
a) True
b) False
Answer: a
Clarification: Acid hydrolysis becomes important in the pulp and paper industry whenever we process wood fibers below pH 2 or so at elevated temperatures.
2. If one treats _________ with 6 % w/w aqueous sulfuric acid under reflux, glucose is obtained in high yield with little secondary decomposition.
a) Cellulose
b) Fructose
c) Starch
d) Lignin
Answer: a
Clarification: If one treats cellulose (which has been swelled in 72 % w/w sulfuric acid at room temperature) with 6 % w/w aqueous sulfuric acid under reflux, glucose is obtained in high yield with little secondary decomposition.
3. If _________ are treated with strong acid such as 20% sulfuric acid at high temperatures, they are first hydrolyzed to the component _________
a) Polysaccharides, monosaccharides
b) Monosaccharides, polysaccharides
c) Fructose, cellulose
d) Lignin, pulp
Answer: a
Clarification: If polysaccharides are treated with strong acid such as 20% sulfuric acid at high temperatures, they are first hydrolyzed to the component monosaccharides.
4. One can reduce the reducing end of mono- or polysaccharides by using sodium borohydride (NaBH4) under _________ conditions at room temperature.
a) Acidic
b) Basic
c) Alkaline
d) Neutral
Answer: c
Clarification: One can reduce the reducing end of mono- or polysaccharides by using sodium borohydride (NaBH4) under alkaline conditions at room temperature.
5. Under conditions of dilute alkali (perhaps 0.1 M NaOH at 100°C) _________ will slowly undergo a reaction that causes C-2 epimerization (a change in configuration of the second carbon atom).
a) Polymers
b) Polysaccharides
c) Monosaccharides
d) Fructose
Answer: c
Clarification: Under conditions of dilute alkali (perhaps 0.1 M NaOH at 100°C) monosaccharides (and the reducing group of polysaccharides) will slowly undergo a reaction that causes C-2 epimerization (a change in configuration of the second carbon atom).
6. What is the name of the question mark area?
a) 25% H2SO4, Reflux
b) 6% H2SO4, Reflux
c) Dilute OH-
d) Maximum Heat
Answer: c
Clarification: Under conditions of dilute alkali (perhaps 0.1 M NaOH at 100°C) monosaccharides (and the reducing group of polysaccharides) will slowly undergo a reaction that causes C-2 epimerization (a change in configuration of the second carbon atom)
7. What is the name of the question mark area?
a) 25% H2SO4, Reflux
b) 6% H2SO4, Reflux
c) Dilute OH-
d) Maximum Heat
Answer: a
Clarification: The reaction of hexoses, or polymers of hexoses such as cellulose, starch, and glucomannans, produces 5- (hydroxymethyl)-2-fiirfiiral that is not volatile and undergoes decomposition to levulinic acid and numerous other compounds.
8. What is the name of the question mark area?
a) 25% H2SO4, Reflux
b) 6% H2SO4, Reflux
c) Dilute OH-
d) Maximum Heat
Answer: a
Clarification: The reaction of hexoses, or polymers of hexoses such as cellulose, starch, and glucomannans, produces 5- (hydroxymethyl)-2-fiirfiiral that is not volatile and undergoes decomposition to levulinic acid and numerous other compounds.
9. What is the name of the question mark area?
a) 25% H2SO4, Reflux
b) 6% H2SO4, Reflux
c) Dilute OH-
d) Maximum Heat
Answer: b
Clarification: If one treats cellulose (which has been swelled in 72 % w/w sulfuric acid at room temperature) with 6 % w/w aqueous sulfuric acid under reflux, glucose is obtained in high yield with little secondary decomposition.
10. What is the name of the question mark area?
a) 25% H2SO4, Reflux
b) 6% H2SO4, Reflux
c) Dilute OH-
d) Maximum Heat
Answer: b
Clarification: If one treats cellulose (which has been swelled in 72 % w/w sulfuric acid at room temperature) with 6 % w/w aqueous sulfuric acid under reflux, glucose is obtained in high yield with little secondary decomposition.
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