Organic Chemistry Multiple Choice Questions on “Prepartions of Glycols”.
1. Which of the following reagent can be used to carry out this synthesis of glycol?
a) Benedict reagent
b) Baeyer’s reagent
c) Barfoed reagent
d) Seliwanoff reagent
Answer: b
Clarification: Cold dilute alkaline solution of Bayer’s reagent can be used to carry out this synthesis of glycol.
2. Which of the following is the industrial method of formation of glycol?
a) Hydroxylation of alkene by Bayer’s reagent
b) From 1,2-dibromoethane
c) Oxidation of ethylene and using Ag as catalyst
d) Ethylene treatment with HOCl
Answer: c
Clarification: In the industrial preparation of ethylene glycol, ethylene (IUPAC name: ethene) is oxidized to ethylene oxide (IUPAC name: oxirane) using oxygen and a silver catalyst. Ethylene oxide is then reacted with water at high temperature or in the presence of an acid catalyst to produce ethylene glycol. Diethylene glycol is a useful by-product of this process.
3. Which type of product is formed when Cold dilute alkaline solution of Bayer’s reagent reacts with alkene?
a) Syn-glyol
b) Syn- and anti-geometry will not be there in glycol
c) Anti-glyol
d) Trans glycol
Answer: a
Clarification: On hydroxylation product is formed when Cold dilute alkaline solution of Bayer’s reagent reacts with alkene is syn-glycol.
4. Which of the following statement is not true about preparation of alcohol?
a) French chemist Charles-Adolphe Wurtz (1817–1884) first prepared ethylene glycol in 1856
b) First synthesis of glycol was from “ethylene iodide” (C2H4I2) with silver acetate and then hydrolyzed the resultant “ethylene diacetate” with potassium hydroxide
c) It was synthesized from ethylene dichloride in Germany and used as a substitute for glycerol in the explosives industry
d) There is no biological process for the synthesis of glycol
Answer: d
Clarification: Glycol can be synthesised biologically, example: The caterpillar of the Greater wax moth, Galleria mellonella, has gut bacteria with the ability to degrade polyethylene (PE) into ethylene glycol.
5. What will be the compound A which can be used to carry out this synthesis of glycol?
a) RCOR’
b) RCO2OH
c) RCHO
d) RCOOH
Answer: b
Clarification: A peroxy acid can be used to carry out this synthesis of glycol as shown in below reaction.
6. What will be the catalyst A which can be used to carry out this synthesis of glycol?
a) Catalyst Cu, 200 – 400℃
b) Catalyst Pt, 100 – 200℃
c) Catalyst Ni, 200 – 400℃
d) Catalyst Ag, 200 – 400℃
Answer: d
Clarification: Catalyst Ag at 200 – 400℃ can be used to carry out this synthesis of glycol as shown in below reaction.
